Log multiplayer events (player joined/left and chat)

[Jmgr]

This logs player events (joined, left) and the chat, as well as player errors.

Fixes #672.

[qndel]

Your indentation doesn't match

[AJenbo]

I'm wondering if this should be behind a flag, or set to a specific log level like SDL_LogVerbose

[Jmgr]

I'm wondering if this should be behind a flag, or set to a specific log level like SDL_LogVerbose

Can do, but this would be also applicable at other places I think. We could also add a debug log level that could help with debugging certain features. Happy to make this change for this PR though, as you want.

[qndel]

I'm wondering if this should be behind a flag, or set to a specific log level like SDL_LogVerbose

Can do, but this would be also applicable at other places I think. We could also add a debug log level that could help with debugging certain features. Happy to make this change for this PR though, as you want.

https://pastebin.com/Xfdjsj1F Maybe parts of this can be reused

[qndel]

https://github.com/diasurgical/devilutionX/pull/3722 Replaced with chatlog.

[AJenbo]

This looks to be more about logging to an external place which #3722 doesn't deal with :)