Add "isUnconferenceRoom" flag or similar directly to room data

[lazerwalker]

Currently, src/components/NoteWallView.tsx contains a hardcoded array of roomIDs to use for automatic unconferencing room assignment.

Every year since 2022, we have come close to forgetting to update this.

It would be nice if this were automated. I'm imagining there can be a flag on a Room JSON blob that specifies it's an unconference room, and then the NoteWall "assign unconference rooms" function can filter the full set of roomData to grab all of the rooms flagged as unconference rooms.

Could also just rely on our convention of prefixing each room name with unconf (e.g. unconfArchery), but since that needs to be smart enough to e.g. exclude unconferencingHub that's probably too clever by a half compared to an explicit flag.