Fix #6468: don't store version of AIs-started-via-console in name

You can do: "startai myai.3", which starts version 3 of "myai".
This is very useful for testing save/load code between different
versions of your AI.

However, when using this syntax, the AI got saved as "myai.3" as
name of the AI, instead of "myai". This caused several problems,
like indicating to the user the AI could not be found, but still
load the AI. But in all cases, the AI never got the chance to
load the saved data, making the whole reason this exists pointless.

By splitting the name and version already in the console command,
the code becomes simpler and AIs started this way now follow the
normal flow after initialization.

Remove: console command "content select all" (#8363)

The intention of this function was that you could download
everything after a filter was applied; but this never really
took off. Instead, a select few people used this functionality
to download every available package on BaNaNaS. This is not in
the spirit of this service. Additionally, these few people were
good for 70% of the consumed bandwidth of BaNaNaS.

Fix: Display banlist's indexes correctly

Bug introduced via commit ab711e6942

Feature #7756: Allow server to supply a reason to kicked/banned clients

This commit adds the missing feature of allowing the server owner to
provide a reason for kicking/banning a client, which the client sees in
a pop-up window after being kicked. The implementation extends the
network protocol by adding a new network action called
NETWORK_ACTION_KICKED that is capable of having an error string, unlike
the other network error packages. Additionally, the kick function
broadcasts a message to all clients about the kicked client and the
reason for the kick.

Feature: NewGRF callback profiling (#7868)

Adds a console command newgrf_profile to collect some profiling data about NewGRF action 2 callbacks and produce a CSV file.

Add: 'getsysdate' console command (#7658)

Add `getsysdate` console command to display system's local time, which is might be useful to check current time in script logging.

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.

Feature: Framerate display window (#6822)

Frame rate and various game loop/graphics timing measurements and graphs. Accessible via the Help menu, and can print some stats in the console via the fps command.