MSC2836: Threading - part one (#1589)

* Add mscs/hooks package, begin work for msc2836

* Flesh out hooks and add SQL schema

* Begin implementing core msc2836 logic

* Add test harness

* Linting

* Implement visibility checks; stub out APIs for tests

* Flesh out testing

* Flesh out walkThread a bit

* Persist the origin_server_ts as well

* Edges table instead of relationships

* Add nodes table for event metadata

* LEFT JOIN to extract origin_server_ts for children

* Add graph walking structs

* Implement walking algorithm

* Add more graph walking tests

* Add auto_join for local rooms

* Fix create table syntax on postgres

* Add relationship_room_id|servers to the unsigned section of events

* Persist the parent room_id/servers in edge metadata

Other events cannot assert the true room_id/servers for the
parent event, only make claims to them, hence why this is
edge metadata.

* guts to pass through room_id/servers

* Refactor msc2836 to allow handling from federation

* Add JoinedVia to PerformJoin responses

* Fix tests; review comments

roomserver/internal/input/input.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/Shopify/sarama"
+	"github.com/matrix-org/dendrite/internal/hooks"
 	"github.com/matrix-org/dendrite/roomserver/acls"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/storage"
@@ -61,7 +62,11 @@ func (w *inputWorker) start() {
 	for {
 		select {
 		case task := <-w.input:
+			hooks.Run(hooks.KindNewEventReceived, &task.event.Event)
 			_, task.err = w.r.processRoomEvent(task.ctx, task.event)
+			if task.err == nil {
+				hooks.Run(hooks.KindNewEventPersisted, &task.event.Event)
+			}
 			task.wg.Done()
 		case <-time.After(time.Second * 5):
 			return