Add support for settings in Gmod

[kowalski7cc]

Add the support for setting like healt and stuff like that...

[light-yagami]

Hello, I installed a dedicaced server but after a few rounds, servers ask to vote for another gamemode (only Prop Hunt is on) and after this, we have to vote for maps, but no one appears, any soluce?

[andrewtheis]

@light-yagami - Please report a new issue for this.

@kowalski7cc - It doesn't appear that modifying the settings configuration in the gamemode.txt file does anything. Is it possible to add gamemode-specific settings like this? Do other game modes do this?

[kowalski7cc]

https://github.com/garrynewman/garrysmod/blob/master/garrysmod/gamemodes/sandbox/sandbox.txt