Update to Nextcloud 13.0.7 - Released

The last update before Nextcloud 15.

Todos

• Bookmarks App Update to version 0.12.2 (done)
• Talk App Update to version 3.2.6 (done)
• Music App Update to version 0.9.2 (done)
• Test the migration of existing customer (done)
• Eat your own Dogfood. Update our own Clouds  (done)
• Migration all existing customers (done)