Mineau Jean-Marie authored Sep 21, 2020 and chirac committed Jan 24, 2021

changes:

Article:
remove COTISATION_TYPE, duration(_days), type_cotisation
add duration(_days)_connection, duration(_days)_membership

Vente:
remove COTISATION_TYPE, duration(_days), type_cotisation
add duration(_days)_connection, duration(_days)_membership
add method `test_membership_or_connection()` to replace
`bool(type_cotisation)`

Cotisation:
remove COTISATION_TYPE, date_start, date_end, type_cotisation
add date_start_con, date_end_con, date_start_memb, date_end_memb

create_cotis(date_start=False) -> create_cotis(date_start_con=False, date_start_memb=False)

+ migration
+ changes to use the new models in the remaining of the code