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

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 :)

Adds some hardening against potential CSP bypassed.

Fix #10514

Minimum size is 3 = 46656 tokens, maximum size is 64, which is what our DB allows.

If client does not send content length header on webdav upload (e.g. because the content comes from a stream and its length is not predictable) the put() method should not try to compare the content length value with the actually amount of received data, because this will always fail and results in a BadRequest exception. So the check will only be performed if $_SERVER['CONTENT_LENGTH'] is set.

Fix #10847