Enable parallel runs of quotest

[KitsuneRal]

The way quotest works now requires exclusive interaction with the room (there's joining and leaving, in particular, and there's an intention to add room creation and deletion to the mix). It would be great if every execution could work independently, with some observing instance to enable joining/leaving those transient rooms. With one room per invocation, two test users (one managing the room and one visiting it) should probably be enough.