* Consolidation of roomserver APIs
* Comment out alias tests for now, they are broken
* Wire AS API into roomserver again
* Roomserver didn't take asAPI param before so return to that
* Prevent roomserver asking AS API for alias info
* Rename some files
* Remove alias_test, incoherent tests and unwanted appservice integration
* Remove FS API inject on syncapi component
* Make backfill work for shared history visibility
* fetch missing state on backfill to remember snapshots correctly
* Fix gmsl to not mux in auth events into room state
* Whoops
* Linting
* Initial cut for backfilling
The syncserver now asks the roomserver via QueryBackfill (which already
existed to *handle* backfill requests) which then makes federation requests
via gomatrixserverlib.RequestBackfill.
Currently, tests fail on subsequent /messages requests because we don't know
which servers are in the room, because we are unable to get state snapshots
from a backfilled event because that code doesn't exist yet.
* WIP backfill, doesn't work
* Make initial backfill pass checks
* Persist backfilled events with state snapshots
* Remove debug lines
* Linting
* Review comments
