Uuid fix

My intention was to just fix the UUID stuff, but then I started digging in to how backfire works and ended up writing the game initialization logic too.

When you load the board, it checks all existing games for games with only 1 player. If no games exist, or all games are full, it creates a new one.

If you load this game right now and someone else is also connected, you'll see them move the pieces around along with you :dancer: