Waiting lobbies should show the number of players needed in the sidebar

[haykam821]

The 'waiting for players...' message isn't useful for players wondering what the exact limits of a game are as the exact behavior of the waiting lobby is opaque to players. This message could potentially be expanded to indicate how many players are needed before the threshold is met, or if all players are in the game already, how many players are needed before the minimum amount of players is met.