Add sv_maplist to configure which maps the server sends to authenticated clients. Possible values:

• none (or any invalid value) - send no maps

• standard - only send standard maps (defined by the map checker)

• all (default) - send all maps

Server must be restarted for the setting to take effect, as the maplist is only loaded once. The config variable is a string because it's more readable and can potentially be extended in the future to specify custom lists like `sv_mapl...