Improve deletion of databases from Django administration page

The current behaviour when deleting a database from Django administration page is as follows:

• Deletion of the 'Database' entry
• Deletion of the 'Database protocol' entries
• Deletion of the 'Database set' entries

Since adding a database may also imply adding a 'Database set template' and 'Database output's, it would be better to remove these entries as well, when they are not used by any other databases installed on the platform.

Tip: Use Django's Admin actions (https://docs.djangoproject.com/en/dev/ref/contrib/admin/actions/) to overload a "Database" delete to trigger all these actions.

This is now done. We don't use admin actions, just improved the object model so that the functioning is consistent.

Status changed to closed

mentioned in commit 9fd261b7