ERP5: revert to using func code
Replaces https://lab.nexedi.com/nexedi/slapos/merge_requests/1178 by a much simpler approach.
Needs https://lab.nexedi.com/nexedi/erp5/merge_requests/1634 on ERP5 side
Replaces https://lab.nexedi.com/nexedi/slapos/merge_requests/1178 by a much simpler approach.
Needs https://lab.nexedi.com/nexedi/erp5/merge_requests/1634 on ERP5 side