Add: [Script] GSAsyncMode to set async mode of gamescript commands (#10913)

In asynchronous mode, don't wait for result of executed command,
just fire-and-forget, and return estimated cost/result

Change: Replace ScriptLog data array with std::deque. (#10770)

Due to cyclic header dependency this requires moving the data types used
by ScriptLog out of the ScriptLog class.

Fix: crashes to desktop from game scripts when companies disappear

When a game script is in company mode, it pretends to be another company. When
that company disappear (bankruptcy/merger), the game script still uses that
company and it keeps calling functions as if it is that company.

For example, ScriptEngine::IsBuildable internally dereferences Company without
checks, causing a null dereference for any ScriptEngine function when called
from a company scope of a company that has disappeared.

Guard against this by extending the ScriptCompanyScope::IsValid check to also
check for the company still being active.

Codechange: use GSCompanyMode::IsValid, IsDeity, and the precondition helpers

Direct 1:1 replacements in the code, and comments now refer to either
GSCompanyMode::IsValid or GSCompanyMode::IsDeity instead of several variations
on "company mode active" or "no company mode active".

Codechange: Template DoCommand 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.

Fix: ScriptObject::DoCommand could modify "text" while defined "const"

This could have unwanted side-effects, as it could change the
source for ever and ever.

Codechange: rename str_validate to StrMakeValid(InPlace) (#9304)

This to be more explicit the function changes the value, and not
returns yes/no.

Fix b3fd7879: Ignore command flags when verifying script commands

Multiplayer games has the server add some flags to the cmd value during the handling.
These flags should not be included in the verification, mask them out. Without this
masking out, scripts tend to die when executing their first command in multiplayer.

Change: Limit memory allocations for each Squirrel instance

This can avoid out-of-memory situations due to single scripts using up the entire address space.
Instead, scripts that go above the maximum are killed.
The maximum is default 1 GB per script, but can be configured by a setting.

Remove: ENABLE_NETWORK switch

This switch has been a pain for years. Often disabling broke
compilation, as no developer compiles OpenTTD without, neither do
any of our official binaries.

Additionaly, it has grown so hugely in our codebase, that it
clearly shows that the current solution was a poor one. 350+
instances of "#ifdef ENABLE_NETWORK" were in the code, of which
only ~30 in the networking code itself. The rest were all around
the code to do the right thing, from GUI to NewGRF.

A more proper solution would be to stub all the functions, and
make sure the rest of the code can simply assume network is
available. This was also partially done, and most variables were
correct if networking was disabled. Despite that, often the #ifdefs
were still used.

With the recent removal of DOS, there is also no platform anymore
which we support where networking isn't working out-of-the-box.

All in all, it is time to remove the ENABLE_NETWORK switch. No
replacement is planned, but if you feel we really need this option,
we welcome any Pull Request which implements this in a way that
doesn't crawl through the code like this diff shows we used to.