Should be able to trigger promotion from the Registry & from Airflow
Registry would pick up the events from either starting point
Registry should create a Trigger when promotion is triggered from the Registry
Airflow should send events (possibly on a new queue?) throughout the publication process.
Registry should create Runs and Events when events start coming from Airflow (regardless of trigger, but should self-associate with a trigger if one exists)
Airflow should send a clear signal regarding success or failure of publication along with the version currently published (and the version we were trying to publish)
Registry should update the Collection model's published_version and staged_version fields on successfully running the Index Collection task
Registry should flag if a Collection's published_version and should_be_published_version are different and no Run is currently running (registry should also flag if a Collection's staged_version and should_be_staged_version are different and no Run is currently running).
Should be able to trigger promotion from the Registry & from Airflow Registry would pick up the events from either starting point