chore: Refactor backlinks and revisions (#1611)

* Update backlinks service to not rely on revisions

* fix: Add missing index for finding backlinks

* Debounce revision creation (#1616)

* refactor debounce logic to service

* Debounce slack notification

* Revisions created by service

* fix: Revision sidebar latest

* test: Add tests for notifications

server/models/Event.js

@@ -48,6 +48,12 @@ Event.afterCreate((event) => {
   events.add(event, { removeOnComplete: true });
 });
 
+// add can be used to send events into the event system without recording them
+// in the database / audit trail
+Event.add = (event) => {
+  events.add(Event.build(event), { removeOnComplete: true });
+};
+
 Event.ACTIVITY_EVENTS = [
   "users.create",
   "documents.publish",