Implement key uploads (#1202)

* Add storage layer for postgres/sqlite

* Return OTK counts when inserting new keys

* Hook up the key DB and make a test pass

* Convert postgres queries to be sqlite queries

* Blacklist test due to requiring rejected events

* Unbreak tests

* Update blacklist

internal/config/config_test.go

@@ -56,6 +56,7 @@ database:
   room_server: "postgresql:///room_server"
   appservice: "postgresql:///appservice"
   current_state: "postgresql:///current_state"
+  e2e_key: "postgresql:///e2e_key"
 listen:
   room_server: "localhost:7770"
   client_api: "localhost:7771"
@@ -66,6 +67,7 @@ listen:
   edu_server: "localhost:7778"
   user_api: "localhost:7779"
   current_state_server: "localhost:7775"
+  key_server: "localhost:7776"
 logging:
   - type: "file"
     level: "info"