Remove: setting "no_http_content_downloads" (#12058)

As we now use HTTPS, it is very likely this will work on most systems.
For systems that do have HTTPS blocked, it will fail instantly,
and it will fallback to TCP anyway. That makes this setting no longer
very useful.

Codechange: refactor DecodeHexText to a generic purpose ConvertHexToBytes (#11866)

DecodeHexText() does more than just decoding hex. ConvertHexToBytes()
now only does pure hex decoding. This required a bit of refactoring
for the code using DecodeHexText().

Codechange: Don't keep autosave_interval in std::chrono::minutes.

This variable is saved as a setting which requires the variable type to be known, but std::chrono::minutes may vary depending on system type.

Instead, keep as uint32_t and convert to std::chrono::minutes only when setting the timer.

Codechange: Add const versions of GetItem/GetGroup, and sprinkle liberally.

Non-const version of GetItem is not needed.

Codechange: Use std::list instead of C-linked list for ini files.

This removes self-management of memory with new/delete and allows simpler iteration.

Codechange: Remove create parameter from IniLoadFile::GetGroup.

GetGroup now only returns nullptr if the group does not exist.
Use GetOrCreateGroup to create a group.

This avoids creating groups while reading ini files.

Codechange: Split GetGroup into GetGroup/GetOrCreateGroup.

This follows the pattern used for GetItem/GetOrCreateItem, and allows use
of references where we know the group must exist.

Codechange: Add CreateGroup/CreateItem methods for ini files.

This abstracts the internals a bit.

Codechange: automatic adding of _t to (u)int types, and WChar to char32_t

for i in `find src -type f|grep -v 3rdparty/fmt|grep -v 3rdparty/catch2|grep -v 3rdparty/opengl|grep -v stdafx.h`; do sed 's/uint16& /uint16 \&/g;s/int8\([ >*),;[]\)/int8_t\1/g;s/int16\([ >*),;[]\)/int16_t\1/g;s/int32\([ >*),;[]\)/int32_t\1/g;s/int64\([ >*),;[]\)/int64_t\1/g;s/ uint32(/ uint32_t(/g;s/_uint8_t/_uint8/;s/Uint8_t/Uint8/;s/ft_int64_t/ft_int64/g;s/uint64$/uint64_t/;s/WChar/char32_t/g;s/char32_t char32_t/char32_t WChar/' -i $i; done

Codechange: refactor setting conversions and make sure it only happens once

By forcing it only happens once, the first time you upgrade to
a newer client, means you are free to jump between older and newer
versions after that. As they will not resync, the newer setting
can take on any of the (newer) values, without breaking the old
client. And when going to an old client and back, it doesn't
change it back to the converted value anymore.

Codechange: Split GetItem with GetOrCreateItem. (#10952)

`IniGroup::GetItem()` returns nullptr if the item does not exist, but does not if the create parameter is set to true. Resolve CodeQL warnings with `GetOrCreateItem()` which returns a reference to the item instead.

Codechange: Use std::array for GRF(File|Config) parameters.

This simplifies comparison, copying and assignment operations.

Fix: no_http_content_downloads and use_relay_service as private settings (#10762)

Basically, we don't need to know those values when people send in
crash reports.

Codechange: Place gamelog into its own class, along with internal data.

Data is now stored in vectors to avoid manual memory management and
passing lengths around.

Codechange: Template DoCommandP to automagically reflect the parameters of the command proc.

When finished, this will allow each command handler to take individually
different parameters, obliviating the need for bit-packing.

Codechange: Let the compile generate the master command table out of templated command traits.

This is using a non-intrusive type-traits like templated system, which
allows compile-time validation that the command table and the command
enum match up.

Feature: parse the console settings the same way as config settings

Now you can use things like `set server_game_type public` instead of having to
guess the number, which would not be written into the configuration file nor
would it be shown when doing `set server_game_type`.

Codechange: split settings.ini over several files (#9421)

This reduced the load on compilers, as currently for example MacOS
doesn't like the huge settings-tables.

Additionally, nobody can find settings, as the list is massive and
unordered. By splitting it, it becomes a little bit more sensible.

Add: store headers for most savegame chunks

When a header is added, the chunk changes from CH_ARRAY type to
CH_TABLE type.

Feature: framework to make savegames self-descriptive

We won't be able to make it fully self-descriptive (looking at you
MAP-chunks), but anything else can. With this framework, we can
add headers for each chunk explaining how each chunk looks like
in detail.

They also will all be tables, making it a lot easier to read in
external tooling, and opening the way to consider a database
(like SQLite) to use as savegame format.

Lastly, with the headers in the savegame, you can freely add
fields without needing a savegame version bump; older versions
of OpenTTD will simply ignore the new field. This also means
we can remove all the SLE_CONDNULL, as they are irrelevant.

The next few commits will start using this framework.

Change: move sensitive information to secrets.cfg and private information to private.cfg

We often ask people for their openttd.cfg, which now includes their
passwords, usernames, etc. It is easy for people to overlook this,
unwillingly sharing information they shouldn't.

By splitting this information over either private.cfg or secrets.cfg,
we make it more obvious they shouldn't be sharing those files, and
hint to what is inside them.

Codechange: simplify SaveVersionInConfig()

Clearly someone really wanted to generalize the function, but
in reality it makes it a lot longer than needed. Let's keep it
simple.

Codechange: C++-ify the usage of IniFile in settings.cpp

Instead of creating the object on heap and use a pointer, create
the object on stack and use a guaranteed-not-null pointer.
The size of IniFile doesn't warrent the forcing to heap.

Additionally, use a subclass instead of a function to do some
initial bookkeeping on an IniFile meant to read a configuration.

Codechange: move network-related settings out of settings.ini

This to prepare the code to split up network-related settings
into private / secrets / generic.

Fix #9386: compilers failing to compile with LTO by using variants instead of new + unique_ptr

With std::variant all memory can be figured out at compile time, so the compiler needs to keep track of fewer elements. It also saves out a unique_ptr and its memory management, over a slight impact for resolving a setting.

Codechange: remove overloading on UpdateServiceInterval

One UpdateServiceInterval has two parameters to update the service interval for a vehicle type, the other for all vehicle types at once. Rename the latter to help with function resolution for the introduction of variants.

Codechange: mark chunks that are not stored as CH_READONLY

This makes it easier to spot chunks that have a save_proc that
is a nullptr, but also prevents confusion, where it looks like
the CH_ type of a chunk has influence on how it is being read.
It is not, it is only used for saving.

Change: rework several CH_RIFF chunks to use CH_ARRAY instead

This adds two byte extra to those chunks, and might feel a bit
silly at first. But in later changes we will prefix CH_ARRAY with
a table header, and then this change shines.

Without this, we could still add headers to these chunks, but any
external reader wouldn't know if the CH_RIFF has them or not. This
way is much more practical, as they are now more like any other
chunk.

Codechange: ability to store structs and list of structs in savegames

The commits following this will use this new functionality.

Currently, a few places do this manually. This has as drawback that
the Save() and Load() code need to be in sync, and that any change
can result in (old) savegames no longer loading. In general, it is
annoying code to maintain.

By putting everything in a description table, and use that for
both Save() and Load(), it becomes easier to see what is going on,
and hopefully less likely for people to make mistakes.

Codechange: replace IConsolePrintF with IConsolePrint and fmt formatting

Also make some strings more consistent with the rest of the console strings.

Change: unify the style of console error messages and convert to fmt

Always start with a capital, do not add "ERROR: " in front of it.

Codechange: make [Save|Load]Settings() behave more like other Save/Load code (#9335)

Prepare the full description and send it to SlObject. This does
require some code to be able to read to a SLE_VAR_NULL, like strings
etc, as there is no way to know their length beforehand.

Codechange: merge guiflags and flags in settings .ini files

It was rather confusing which one was for what, especially as some
SaveLoad flags were settings-only. Clean up this mess a bit by
having only Setting flags.

Codechange: move SLF_NO_NETWORK_SYNC into settings

It is a settings-only flag, so don't pollute SaveLoad code with it.

Codechange: move SLF_NOT_IN_SAVE into settings

It is a settings-only flag, so don't pollute SaveLoad code with it.

Codechange: Remove FOR_ALL_CHUNK_HANDLERS

Co-Authored-By: Patric Stout <truebrain@openttd.org>

Codechange: rename SettingGuiFlag to SettingFlag (#9332)

It is a lovely organicly grown enum, where it started off with
GUI-only flags, and after that a few flags got added that can be
considered GUI-only (the GUI disables/enables based on them), to
only have flags added that has nothing to do with the GUI.

So be less confusing, and rename them to what they do.

Additionally, I took this opportunity to rename 0ISDISABLED to
reflect what it really does.

Codechange: C++-ify lists for SaveLoad (#9323)

Basically, this changes "SaveLoad *" to either:
1) "SaveLoadTable" if a list of SaveLoads was meant
2) "SaveLoad &" if a single entry was meant

As added bonus, this removes SL_END / SLE_END / SLEG_END. This
also adds core/span.hpp, a "std::span"-lite.

Codechange: use setting name instead of index for CmdChange(Company)Setting (#9306)

This is mostly done as there are now constraints on settings.ini you might not
expected. For example, conditional settings always have to come last, as otherwise
they would influence the index.