Implement new admin delegation feature

[thekk1]

There is a "new" feature called admin right privilege in Nextcloud that allow you to privilege a list of persons or groups to access single sites or single elements of a site (based on the app itself) in the administration site.

See https://docs.nextcloud.com/server/25/admin_manual/configuration_server/admin_delegation_configuration.html

This is maybe a variant of a solution to the issue #7 and for sure a very welcome update to me, because the admin has more things to do than answer user requests. ;-)

[thekk1]

The implementation is not complete.
If I allow non admin persons or groups to setup the approval workflows, they are not able to see or set the invisible tags nor they are able to create some.

[lukasdotcom]

Hi @thekk1,
Sadly that portion had to be disabled for non admins because they wouldn't be able to select the invisible tags.

[lukasdotcom]

Hi @thekk1,
After further discussion a solution was found with tag creation by changing the default tag creation to restricted instead of invisible and allowing admin delegated users to create those tags. This is implemented in #319