An endpoint was created in zerver/views. Basic rate-limiting was
implemented using RealmAuditLog. The idea here is to simply log each
export event as a realm_exported event. The number of events
occurring in the time delta is checked to ensure that the weekly
limit is not exceeded.
The event is published to the 'deferred_work' queue processor to
prevent the export process from being killed after 60s.
Upon completion of the export the realm admin(s) are notified.
Wyatt Hoodes