Added Shared with link sidebar section in files app

remove file locking - code will continue to live in it's own app

Toggle app navigation not only on mobile, but on desktop as well

Fix mime type returning for shared with others files

Simulate apps database schema update on upgrade

Kill permissions table

- the file/folder's permission is now stored in the file cache
- BackGroundWatcher has been removed - this has meanwhile be replaced by occ files:scan which can be executed in a cron jobs
- increase version to trigger database migration

remove obsolete placeholder call, fix #8881

Update SabreDAV to 1.8.10

This prevents routes like "core/js/oc.js" to automatically load apps and
trigger their update prematurely.

minimal mail template editor for administrators

[versioning] let the file cache track the size of the versions

personal settings: unbold clients header and remove obsolete CSS

When upgrade, also simulate the database schema update for apps before
doing the actual upgrade.

Update share action text to display owner/recipients

explicit position:relative for app-content, fixes first run layout