Celery beat setup doesn't scale correctly to multiple processes

[rgossiaux]

Our Celery setup right now has beat running with every celery worker. During MH this year there were moments where the worker got backed up and we scaled up the # of workers, but when we did that, we noticed that Beat tasks were being duplicated.

Celery doesn't support this out of the box. We're using django-celery-beat and there might be some way to avoid this using that. There are also projects like https://github.com/sibson/redbeat and https://github.com/ybrs/single-beat