[suggestion] Spectator mode enhancement

[ywgATustcbbs]

Allow players to mark themselves as soft spectators in a lobby. This would solve the issues that a player gets leadership while afk. The suggestion is:

1. add a cvar, cl_spectate for example.
2. When an active leader quit the lobby, always assign leadership to a player without cl_spectate mark unless there is no other active player
3. When an active player joins a server lobby and the leader is marked as spectating, reassign leadership to the active player
4. Do not count spectating players When voting

This should solve the issues of too many afk players take over a server and active players can't do anything via voting

Additional advantages:

1. Can add a button/checker in lobby to toggle/show spectator status
2. If the game detects a player as afk, then the spectator mark should be set automatically
3. Since the lobby browser will be redesigned, perhaps it can show both the number of active players and spectators