Merge pull request #8032 from owncloud/fs-backend-registration

apps/files_external/appinfo/app.php

apps/files_external/lib/amazons3.php

apps/files_external/lib/config.php

apps/files_external/lib/dropbox.php

apps/files_external/lib/ftp.php

apps/files_external/lib/google.php

apps/files_external/lib/smb.php

apps/files_external/lib/swift.php

apps/files_external/lib/webdav.php

apps/files_external/tests/dynamicmountconfig.php