Fix: crash when joining a server again after a TCP disconnect (#9453)

"my_client" wasn't always free'd when a game ended. "my_client"
keeps a reference inside the PT_NCLIENT pool. The rest of the
code assumes that when you are not in a game, it can freely
reset this pool.
In result: several ways to trigger a use-after-free.

Update: Translations from eints
english (us): 15 changes by 2TallTyler
korean: 12 changes by telk5093
russian: 3 changes by Ln-Wolf
portuguese: 12 changes by azulcosta
polish: 98 changes by pAter-exe

Update: Translations from eints
swedish: 1 change by joeax910
romanian: 36 changes by ALEX11BR

Feature: allow the use of TURN to connect client and server together

TURN is a last resort, used only if all other methods failed.
TURN is a relay approach to connect client and server together, where
openttd.org (by default) is the middleman.

It is very unlikely either the client or server cannot connect to
the STUN server, as they are both already connected to the Game
Coordinator. But in the odd case it does fail, estabilishing the
connection fails without any further possibility to recover.

Fix: OverflowSafeInt could underflow

Notably, a company with an extremely negative amount of money would
suddenly become very rich

Fix: OverflowSafeInt negation not handling INT64_MIN

INT64_MIN negated is above INT64_MAX, and would overflow.
Instead, when negating INT64_MIN make it INT64_MAX.
This does mean that -(-(INT64_MIN)) != INT64_MIN.

Update: Translations from eints
german: 1 change by danidoedel

Update: Translations from eints
estonian: 1 change by siimsoni
russian: 20 changes by Ln-Wolf

Feature: [Network] Optionally send NewGRF names with NewGRFs in GameInfo

Before 8a2da49 the NewGRF names were synchronized using UDP packets, however
those have been removed. With this a new version of the GameInfo packet is
introduced that allows to specify the type of serialisation happens for
NewGRFs. Either only the GRF ID and checksum, or those two plus the name of
the NewGRF.
On this request for local servers will send the NewGRFs names.
The Game Coordinator will get the names on the first registration, and after
that only the GRF ID and checksum.

Remove: the concept of UnknownGRFs

These were filled with "<Unknown>" (before 8a2da49) and later their name would get filled via UDP requests to the server. These UDP packets do not exist anymore, so they will always remain "<Unknown>".
Remove that logic and just use the generic translated error GRF UNKNOWN string instead.

Update: Translations from eints
korean: 2 changes by telk5093
catalan: 3 changes by J0anJosep
french: 17 changes by glx22
portuguese: 1 change by azulcosta
portuguese (brazilian): 15 changes by Vimerum

Feature: Persistant rotation of numbered auto/netsave after restart (#9397)

It was always starting from 0 on openttd restart.
Now the most recent auto/netsave number will be used as a base to generate the next filename.

Update: Translations from eints
spanish (mexican): 1 change by absay
dutch: 15 changes by Afoklala
portuguese: 1 change by azulcosta

Feature: allow the use of STUN to connect client and server together

This method doesn't require port-forwarding to be used, and works for
most common NAT routers in home setups. But, for sure it doesn't work
for all setups, and not everyone will be able to use this.

Update: Translations from eints
swedish: 14 changes by joeax910

Add: inform clients what game-script a server is running (#9441)

Co-authored-by: The Dude <thedude@novapolis.net>

Update: Translations from eints
spanish (mexican): 1 change by absay
finnish: 14 changes by hpiirai

Update: Translations from eints
korean: 1 change by telk5093
portuguese: 1 change by azulcosta

Update: Translations from eints
spanish (mexican): 4 changes by absay
english (us): 13 changes by 2TallTyler
korean: 5 changes by telk5093
german: 13 changes by Wuzzy2
portuguese: 4 changes by azulcosta
hindi: 6 changes by ritwikraghav14

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`.

Fix: "Search LAN games" used the socket after it was closed (#9437)

Every outgoing connection, either TCP or UDP, triggered
NetworkInitialize(), which triggered NetworkUDPInitialize() which
first closes all connections.

Now the problem was that "Search LAN games" found a server, added
it to the list, after which (over TCP) it queries the server. This
closes all UDP sockets (as that makes sense, I guess?), while the
UDP was still reading from it.

Solve this by simply stop initializing UDP every time we make an
outgoing TCP connection; instead only do it on start-up.

Add: allow setting your server visibility to "invite-only" (#9434)

In this mode you do register to the Game Coordinator, but your
server will not show up in the public server listing. You can give
your friends the invite code of the server with which they can
join.

Update: Translations from eints
spanish (mexican): 29 changes by absay
czech: 11 changes by JustImagine436
korean: 9 changes by telk5093
portuguese: 9 changes by azulcosta
hindi: 28 changes by ritwikraghav14

Feature: join servers based on their invite code

This removes the need to know a server IP to join it. Invite codes
are small (~7 characters) indentifiers for servers, which can be
exchanged with other players to join the servers.

Change: groundwork to allow ServerAddress to use invite codes

Normally TCPConnecter will do a DNS resolving of the connection_string
and connect to it. But for SERVER_ADDRESS_INVITE_CODE this is different:
the Game Coordinator does the "resolving".

This means we need to allow TCPConnecter to not setup a connection
and allow it to be told when a connection has been setup by an external
(to TCPConnecter) part of the code. We do this by telling the (active)
socket for the connection.

This means the rest of the code doesn't need to know the TCPConnecter
is not doing a simple resolve+connect. The rest of the code only
cares the connection is established; not how it was established.

Codechange: track servers with a ServerAddress instead of a NetworkAddress

This allows future extensions to have different ways of referencing
a server, instead of forcing to use IP:port.

Fix a4987233: NewGRFs could no longer be loaded from the NewGRF folder.

This statement was removed by accident, as it felt it could be removed.
But it is used to know if the NewGRF is from the baseset folder or
from the NewGRF folder.

Feature: allow setting (game) coordinator and content server connection strings using environment variables

OTTD_COORDINATOR_CS for the game coordinator defaults to coordinator.openttd.org:3976
OTTD_CONTENT_SERVER_CS for the content server defaults to content.openttd.org:3978
OTTD_CONTENT_MIRROR_CS for the content mirror server defaults to binaries.openttd.org:80

Codechange: use the C++ std::getenv over the POSIX/C getenv

The C++ std::getenv is guaranteed thread-safe by the C++11 specification,
whereas the POSIX/C getenv might not be thread-safe by the C11 specification.

Update: Translations from eints
spanish (mexican): 74 changes by absay
vietnamese: 62 changes by KhoiCanDev

Remove: old server listing via Master Server

This removes all UDP from the game except for a local broadcast
to find LAN games.

So long Master Server, and tnx for all the fish!

Remove: old server announcement to Master Server

As we now use the Game Coordinator for announcements, there is no
longer a need to use the Master Server for this.

Remove: logically dead code from font cache

The outer if statement checks for 'aa' being false, so within the inner
statements anything checking aa will have a known result and the other
branch from there will be dead code.

Fix 11ab3c4: [NewGRF] Overflow when determining cargo mask for string code 9A 1E

9A 1E: Print unsigned word as name of a cargo type (translated for GRF version >= 7).

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.

Update: Translations from eints
spanish (mexican): 44 changes by absay
italian: 2 changes by CoderLel

Update: Translations from eints
spanish (mexican): 54 changes by absay

Fix: reduce the amount of debug messages on -dsl=2 (#9420)

LoadCheck makes it sound like something is really broken while
loading savegames, while it really is perfectly normal, as most
chunks do not implement LoadCheck.

Fix 9e32c618: network revision was always empty (#9419)

Shadowing the variable you intend to write in tends to do that ;)

Update: Translations from eints
spanish (mexican): 6 changes by absay

Update: Translations from eints
portuguese (brazilian): 1 change by Vimerum

Update: Translations from eints
hindi: 26 changes by ritwikraghav14

Update: Translations from eints
catalan: 1 change by J0anJosep

Codechange: Add CMake source group for the saveload compat tables.

While at it, fix the not-working OpenGL sub-group.

Update: Translations from eints
norwegian (bokmal): 1 change by Anolitt
japanese: 1 change by scabtert

Codechange: make savegame-version checks more obvious in SlCompanyLiveries::Load

num_liveries indirectly contained the same information, but this
makes reading these things pretty difficult. So use IsSavegameVersionBefore()
like everywhere else instead.

Codechange: using "until" in function names can be confusing

IsSavegameVersionUntil() did a [0, N] check, not [0, N) as the
name suggests.

Until can be a confusing word, where people consider it to be
including the upperbound. Dictionary states it means "before",
excluding the upperbound. There are long debates about who is right.

So, simply remove away from this ambiguity, and call it "before"
and "before or at". This makes the world easier for everyone.