Notifications for users [Backend]

[SilviaAmAm]

The requirements are the same as in the current version of the app. These are:

• The reviewers should receive a notification and (if configured) an email when there is a list waiting for them to be reviewed. The record manager should receive an email when there are changes to be processed and when all reviewers have approved a list.
• It should be possible for each user to configure whether they want to receive an email
• The admin should be able to configure a template for the notification/email body/subject for each type of email. These are: review request, changes to be processed, reminder to review, all reviews completed.