[Feature] Discord integration - Server switching and joining

[paz]

At the moment, you can only see when a player joined the proxy. If they're unable to join a server then you still see the player joined message but they aren't in the server. This can be kind of annoying in some situations.

A way to resolve this could be to verify the player was able to join a server (the default server, lobby, etc). An extension to this would be to show (or configurably show) which server the player connected to in the join message as well as a server switching message eg {player} switched to {server}.

Another unrelated note, theres plenty of issues that have been solved but are still marked as open.

Thanks for your work on this valuable plugin