SMB/CIFS mounts using ownCloud login, fixes #7843

This PR provides a new mount type, that uses the user's ownCloud login credentials to connect to the SMB/CIFS share. It also has the ability to use the username as the share name, for use with home shares. The username and password are stored as session variables, however I do not consider this a security risk as iRODS already does the same thing.

Please review @blizzz @PVince81 @icewind1991 @DeepDiver1975