Perspective key fetching, some federation room join fixes (#975)

* Update gomatrixserverlib

* Test matrix.org as perspective key server

* Base64 decode better

* Optional strict validity checking in gmsl

* Update gomatrixserverlib

* Attempt to find missing auth events over federation (this shouldn't happen but I am guessing there is a synapse bug involved where we don't get all of the auth events)

* Update gomatrixserverlib, debug logging

* Remove debugging output

* More verbose debugging

* Print outliers

* Increase timeouts for testing, observe contexts before trying to join over more servers

* Don't block on roomserver (experimental)

* Don't block on roomserver

* Update gomatrixserverlib

* Update gomatrixserverlib

* Configurable perspective key fetchers

* Output number of configured keys for perspective

* Example perspective config included

* Undo debug stack trace

* Undo debug stack trace

* Restore original HTTP listener in monolith

* Fix lint

* Review comments

* Set default HTTP server timeout to 5 minutes now, block again when joining

* Don't use HTTP address for HTTPS whoops

* Update gomatrixserverlib

* Update gomatrixserverlib

* Update gomatrixserverlib

* Actually add perspectives

* Actually add perspectives

* Update gomatrixserverlib

dendrite-config.yaml

@@ -17,6 +17,14 @@ matrix:
     trusted_third_party_id_servers:
       - vector.im
       - matrix.org
+    # Perspective key servers which are used when direct key requests fail
+    #key_perspectives:
+    #  - server_name: matrix.org
+    #    keys:
+    #      - key_id: ed25519:auto
+    #        public_key: Noi6WqcDj0QmPxCNQqgezwTlBKrfqehY1u2FyWP9uYw
+    #      - key_id: ed25519:a_RXGa
+    #        public_key: l8Hft5qXKn1vfHrg3p4+W8gELQVo8N13JkluMfmn2sQ
 
 # The media repository config
 media: