fix: Properly sync left rooms

- Remove most usages of `update_membership` in favor
  of directly calling the `mark_as_*` functions
- Store the leave membership event as the value in the
  `userroomid_leftstate` table
- Use the `userroomid_leftstate` table to synchronize the
  timeline and state for left rooms if possible

src/core/matrix/state_res/event_auth.rs

@@ -908,7 +908,7 @@ where
 							false
 						}
 					},
-					| JoinRule::Restricted(_) =>
+					| JoinRule::Restricted(_) => {
 						if membership_allows_join || user_for_join_auth_is_valid {
 							trace!(
 								%sender,
@@ -928,7 +928,8 @@ where
 								 valid authorising user given to permit the join"
 							);
 							false
-						},
+						}
+					},
 					| JoinRule::Public => {
 						trace!(%sender, "join rule is public, allowing join");
 						true