Moved dependency check to the individual backends instead of the config
Conflicts:
apps/files_external/appinfo/app.php
apps/files_external/lib/config.php
Selecting 'SMB/CIFS Auto' in the mounts configuration allows an SMB/CIFS
mount to be configured that uses the credentials of the user logging in to
authenticate to the server.
Optionally, the username can be used as the share name, permitting home shares
to be dynamically mounted.
To make it possible to use the short ownCloud URL (without specifying
webdav.php or remote.php), a new backend is available for ownCloud.
The user must specify the host + context path in the "Url" field (which
is mapped to the "host" parameter) and the subdir to mount in the "Root"
field.
This is to prevent confusion because some users forget to append
webdav.php or remote.php to the WebDAV URL.
Fixes#4923
The stored credentials will be used for and interactions with the iRODS server.
Within the config UI a check box can be used to enable the credential reuse.