Add user-stage command
    
    This patch replaces 'stageuser-add --from-delete' with new command
    user-stage.
    
    Original way always required  to specify first and last name, and
    overall combination of options was hard to manage. The new command
    requires only login of deleted user (user-del --preserve).
    
    https://fedorahosted.org/freeipa/ticket/5041
    
    Reviewed-By: Thierry Bordaz <tbordaz@redhat.com>
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>