Make textdraw pool limits runtime configurable

[itsneufox]

Kept the SDK defaults unchanged. Nothing changes unless the user explicitly sets:

      "textdraw": {
          "global_limit": 256,
          "player_limit": 2048
      }

Legacy server.cfg options are also supported:

max_global_textdraws 256
max_player_textdraws 2048

Custom limits are reported during startup. If an invalid value is provided, the default is used instead.

[Pato-Pastor]

rare neufox W

[devbluen]

Man, that's awesome; it's definitely going to be a big help, since most people use player-textdraws a lot.
I hope your PR gets approved.