Closing the websocket connection is sufficent for deleting/leaving
rooms.

Not actually needed anywhere.

Lists all currently available rooms and has some play/pause logic.
WebRTC integration is still missing.

Add commandline parameter for providing the server certificate.

Does not implement any configuration yet and simply streams an
audiotestsrc.

We can just called shutdown() from stopped(), it does exactly the same.

Otherwise we create reference cycles.

No need for another round-trip via messages to get it from the room.