chore: Move initial avatar upload to background worker (#3727)

* chore: Async user avatar upload processor

* chore: Async team avatar upload

* Refactor to task for retries

* Docs
Include avatarUrl in task props to prevent race condition
Remove transaction around upload fetch request

server/models/Event.ts

@@ -156,6 +156,7 @@ class Event extends IdModel {
     "shares.create",
     "shares.update",
     "shares.revoke",
+    "teams.create",
     "teams.update",
     "users.create",
     "users.update",