[DSRE-658] Add publish to pubsub for glam import migration.

[haroldwoo]

Next step is to modify the import job container to subscribe to the topic and verify msgs prior to importing.

This should be done in dev/stage first with separate subscriptions. Once this is working, we can replace the Airflow GkePodOperators that run the migrate.py with the new GkeCronJob||GkeDeployment in Glam