RESP: Provide a reusable request to fully resolve incomplete groups
    
    After initgroups, the group objects might not be complete, but just
    stubs that contain the SID and the GID. If the caller needs to know the
    group names as well, this request allows them to iterate over the list
    of the groups and resolve them one-by-one.
    
    Reviewed-by: Pavel Březina <pbrezina@redhat.com>
    (cherry picked from commit ed15b405ff95e521df3028fc40360a1547ba84bd)