This PR refactors the app services component. It makes the following changes:
* Each appservice now gets its own NATS JetStream consumer
* The appservice database is now removed entirely, since we just use JetStream as a data source instead
* The entire component is now much simpler and we deleted lots of lines of code 💅
The result is that it should be much lighter and hopefully much more performant.
* Update to matrix-org/gomatrixserverlib#303
* Use `gomatrixserverlib.Client` for phone-home stats
* Use `gomatrixserverlib.Client` for push notifications
* Use `gomatrixserverlib.Client` for appservices
* Use `gomatrixserverlib.Client` for three-PID invites
* Use default transport for AS traffic
* Update gmsl and use default client
* Remove replace
* Fix go.sum
* Update gomatrixserverlib
* Go back to appservices managing their own HTTP clients because argh
* Add missing context
* Tweak AS registration check
* Check appservice usernames using correct function
* Update sytest-whitelist
* Use gomatrixserverlib.Client since that allows us to disable TLS validation using the config
* Add appservice-specific client and ability to control TLS validation for appservices only
* Set timeout on appservice client
* Review comments
* Remove dead code
* Enforce LoginTypeApplicationService after all
* Check correct auth type field
* Add missing routing for PerformDirectoryLookupRequest
* Tweak output
* Fix some bugs in devices
* Don't default to federated room joins in response to invite
* Update sytest-whitelist
* Update comments
* Return correct room ID from PerformJoin
* Fix appservice and EDU server API setup, update sytest-whitelist
* Update sytest-whitelist
