Course reminder framework to notify users to

A great way to support learners in their learning experience is to send them reminders to do things that have a deadline.

Example:

• 10 days after entering the course for the first time
• 5 days after beeing enrolled but never entered the course
• 2 days prior to pre-test deadline but test not yet passed
• ...

With a new reminder tool rules can be defined under which emails or notifications can be generated for users. As this is a special feature and to be more flexible and not clutter the interface we decided against adding it to the course node configuration but to implement a dedicated tool.

The configuration is stored in the database and always works on the run structure, thus changes do not need to be published in the editor.

For more details, see the attached spec.