Bluetooth Party Mode

[marcodejongh]

A big (first world problem) we have when climbing with a bunch of friends on our kilter, is that only 1 person knows what problem is currently on the board. It would be super sick if we could create a kilter "party" similar to how Spotify etc have such features.

Initially, that party mode could just show the current problem, and if people are logged in they could tick it. But if #79 is possible, more options become available, like putting new problems in the queue etc.

Happy to contribute this too, since the backend looks pretty light, I'd probably have a stab at doing this with WebRTC