Allow to customize the type of subdivision used per country
#5563 (closed) restricted the usage of subdivisions without parents on addresses. But this subdivision may not be the most appropriate for the address format introduced by #5493 (closed). This is the case for at least Spain and Italy. On both cases the subdivision is used for address format but it is expected to use the Province type. See:
http://bitboost.com/ref/international-address-formats/italy/