Merge pull request #21790 from owncloud/ext-auth-user-provided

apps/files_external/appinfo/application.php

apps/files_external/controller/globalstoragescontroller.php

apps/files_external/controller/storagescontroller.php

...iles_external/controller/userglobalstoragescontroller.php

apps/files_external/controller/userstoragescontroller.php

apps/files_external/js/settings.js

apps/files_external/lib/auth/authmechanism.php

apps/files_external/lib/auth/iuserprovided.php

apps/files_external/lib/auth/password/userprovided.php

apps/files_external/lib/definitionparameter.php

apps/files_external/lib/failedcache.php

apps/files_external/lib/failedstorage.php

apps/files_external/lib/frontenddefinitiontrait.php

apps/files_external/lib/storageconfig.php

...xternal/tests/controller/globalstoragescontrollertest.php

..._external/tests/controller/userstoragescontrollertest.php

apps/files_external/tests/frontenddefinitiontraittest.php

apps/files_external/tests/js/settingsSpec.js