This also serves as a slight refactor of ENT-392.

https://openedx.atlassian.net/browse/EDUCATOR-389

EDUCATOR-274

This makes it possible to refer to multiple book from a single app.

This also means that Open edX branches will be able to pass bok-choy
tests (at least if the books have already been built.)

This reverts commit 65f13dde.

This reverts commit 88dd85ca, reversing
changes made to bf8aef33.

TNL-6674

Fixes migration error thrown by edxapp-migrate-cms

- Creates a new app under cms
- Sends emails asynchronously on completion of any top-level job
- Moves old user task related cms tests to cms_user_tasks

and a comment and explaining why we import aws.* in the openstack settings.

All programs are now managed using the Django admin on the catalog service. This is the first in a series of commits removing use of the old programs service from edx-platform.

ECOM-4422

Waffle serves as a complement to config models. It's useful in feature rollout situations where you may not want to incur the overhead of creating and committing a migration (required for adding a field to a config model), and also handles gradual, percentage-based rollouts.

ECOM-4422

TNL-5245