hide warning "deletion of this shift is a makeup this action will add a point" if line is not a makeup

in js update members makeup method, fix a bug by not updating makeups_to_do global js variable unless request is successful

mostly #7524 and #7413 so that "cancellations" of shift and shift_templates work fine especially when adding/changing shift

take into account the possibility of several shift_template_registration for one res_partner, but only one active

code cleaning : get rid of quick-and-dirty circular dependency fix by moving some code in separated file