Feature Idea: support Device Sync cluster-side `$currentDate`/`$$NOW`/`$$CLUSTER_TIME`

I love and use Realm in my Flutter mobile app, but there’s one thing I would greatly appreciate to be implemented in future - this is server side timestamps, or some schema data type that will be set to server current time upon synchronization of changeset to MongoDB database.

Right now we have to depend on client device time to be set correctly, and as mobile devices mostly synchronize their time with authoritative sources, I can easily think of some “bad actors” trying to mess with application logic by modifying device local time. Right now only possible way to overcome this is to use Atlas triggers - which is an exaggeration, and on busy Apps it can rise cost substantially.

On the other hand I now it will cause some overhead, as every changeset with such column in schema would introduce additional changeset that would need to be transferred back to client and update Realm out there - but I believe overall benefits of such feature would be much greater.