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

#7422 : change variable names in delete_pair_core and use suppleant_member_id to find member to unsubscribe instead of email matching

#7325 : use suppleant_member_id instead of parent_id or is_associated_people to perform binom checks

allow bdm to configure a message that is displayed when a member selects a creneau matching (day of week, time) from member space

fix computation of new makeups_to_do of titulaire when creating pair by taking into account already selected makeups of suppleant

in makeups screen, update points on ajax success to reflect real point change now performed by more complex logic (this may also helps to detect a failure in ajax call)

extract method, create method to simulate bdm lowering all makeups_to_do and update display with updated nbr of makeups