added methods for CardDAV-implementation

I've updated the bundle to my needs. The my new implementations contain:
+ Route-Access: the BaseUri is automatically set to the defined routing-destination of this bundle
+ method for the login via Symfony into the AuthBackend
+ CardDAV & CalDAV-Backend for managing the Addressbook/Calendar

Could be changed to `if (!empty($config['root_dir']) && $config['plugins']['webdav']) {`.