Thumbnail generation

Removed Log

Added requested changes

Added requested changes.

- Fix code style
- Add exception if file does not exist
- Switch route styling

Replaces https://github.com/owncloud/core/pull/10805

Fix codestyle

Fix codestyle

Migrate to appframework

Fix typo

Some code that I also used for https://github.com/owncloud/administration/pull/11

if dbuser exists try a different one, owncloud/core#108

changed outdated comment

corrected length calculation

changed indentation for else clauses

You can't add int here as hint...

Conflicts:
	core/templates/layout.guest.php

Step one, open guest layout for different styles.

Fixes https://github.com/owncloud/core/issues/11004

Fix #7148 - again :)

Using status.php for this.
I modified status.php to also show, whether we're in maintenance.

Checks every 20 seconds if maintenance is over, if yes: reload.

Adds some hardening against potential CSP bypassed.

Fix #10514

Whenever an upgrade is due, do not load extra user backends

handleRequest() is not called from remote.php or public.php which made these files party available but all included apps in there produced errors.

As the expected behaviour is anyways that a trusted domain warning is shown I moved this to init()

Fixes https://github.com/owncloud/core/issues/10064