Feature request: Implement short alias lookup using configurable list of homeservers.

[swedneck]

For example if i set my custom riot instance to use matrix.org as fallback, trying to join #pixelfed when that alias is not set on my HS will instead join #pixelfed:matrix.org

This would help small servers with discoverability of rooms, as otherwise someone has to manually assign aliases to all popular rooms, or users have to know another HS with an alias for that room.