[RVGL] Lobby whitelisting

[Instant]

A whitelisting mode for lobbies enabled by a launch parameter, where all players are forced to spectate unless the host changes their status to 'racing'.

[kiwi]

Yeah, this would come in handy for some kind of sessions. My upvote for this.

[URV]

+1. Could be useful for more competitive events or tournaments, particularly when people have to register for participation.