Overhaul chat channels

[haykam821]

Chat channels are very limited right now in their enum implementation and could use an overhaul to better integrate with the backend and parties.

Particularly, chat channels should be attached to teams through TeamChat, and an event should be used to query the chat channels that a player has access to. In addition, chat should be global by default, as chat suddenly being routed to team chat when it becomes available is confusing.