Allow random teams

I've often seen people pick a side with people with more game hours, so many lobbies end up with 3000 on the other. Obviously this is no guarantee for a steam roll, but from my experience, it happens often.
When creating a lobby, allow the owner to set an option deciding whether players can directly join the team they want to join. If it's not allowed, there will just be two slots for each class without any team color, and will be assigned randomly when the lobby starts.