Extensible select and enumeration types

and their elements in schema EFFECTIVITY_APPLICATION_XIM taking into account BASED_ON types


 date_and_time_item - EXTENSIBLE SELECT
          event_occurrence

 date_item - EXTENSIBLE SELECT
          event_occurrence

 effectivity_item - EXTENSIBLE SELECT

 external_identification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          externally_defined_effectivity_or_ineffectivity_assignment__aea