* feat!: Add data model for course app API
The current course apps API makes individual queries to determine if a course app is enabled, which can be inefficient. With this change we now have a Django model that contains this information, allowing us to make bulk queries about all the course apps for a course in the API.
It also adds a new signal handler that initialises the status of all course apps in a course on course publish.

* Use celery tasks and a management commands to make cache async

* Review feedback

* update log messages
use separate celery task for each course task