Fix for app groups setting preservation

Admin: Nag about cron and redis settings

Port isTargetAllowed to share 2.0

Moved SQLite setup warning to top.

Introduce public storage class for extending

Adding report support

When writing external storage it is complicated to reimplement IStorage
and many others. This PR provides public classes to be extended to
provider storage specific implementations.

Windows's dead baby, windows's dead!

Filesapi renamefailcase

💀

Don't fetch preview images if `enable_previews` is set to `false`

Add test for duplicate 401 headers on DAV

createMock only accepts a single param

Whenever a rename or copy operation failed on the view, we must throw
an exception instead of just ignoring.

Remove obsolete use var

commit transaction after select query

* Correctly convert OCS permissions params

* Added tests about permissions and public upload

Added read and share permissions instead of all (default ones)

Added positive case

Check also permissions update

Added tests for resharing with public links when the user doesn't have enough permisssions