Extensible select and enumeration types

and their elements in schema PRODUCT_CLASS_MIM taking into account BASED_ON types


 groupable_item - EXTENSIBLE GENERIC_ENTITY SELECT
          package_product_concept_feature
          product_concept_feature

 identification_item - EXTENSIBLE SELECT
          product_class
          product_concept_feature

 versionable_item - EXTENSIBLE SELECT
          product_class
          product_concept_feature