Bans plugin now supports web loading

- You can specify a URL to load bans data from. You can either point it
to a Shine bans config file (from which it will extract the bans data
only) or to a default NS2 BannedPlayers.json file, which it will convert
in memory.
- The bans plugin will intercept calls to and from the web interface and
route it through Shine's ban system.