Implement multiplayer functionality

[stewartanderson3]

Implement sending & receiving each of these signals:

• hello any player -> organizer { userId } (all players should send their status to that userId). Organizer should be added to groupId and organizer-groupId.
• playersListUpdate organizer -> other players
• start any player -> other players
• status any player -> other players { timeLeft?, [userId]: { name, score, board }} (timeLeft is only sent from organizer status)
• result organizer -> other players { players: [{score, name]] }