Fixes https://github.com/vector-im/riot-web/issues/14411
The act of setting/changing the algorithm was causing the update function to be marked, meaning we wouldn't trigger an update until something else happened later. To get around this, and still support internal functions spamming calls without multiple updates, we simply move the guts to an internalized function and make the public interface do a trigger.
The core of this is in the MarkedExecution class, with the remainder of the commit ensuring that the right marks and triggers are in place to do the firing.
Because everything is async/await and run through the RoomListStore, we don't have to worry about self-fed updates in the algorithm classes. This also means we have to trigger pretty much all the time.
Changes to tag ordering / list sorting get hit through two paths, so we mark before we do a bulk update and otherwise assume the call is coming in from outside.
