Add local helpers to handle unixid structure
Samba did remove unixid_from_*() helpers in the upstream commit
c906153cc7af21abe508ddd30c447642327d6a5d (Samba 4.11). Since they are
very simple, make a local copy instead.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1757089
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>