Extensible select and enumeration types

and their elements in schema DOCUMENT_ASSIGNMENT_MIM taking into account BASED_ON types


 document_reference_item - EXTENSIBLE SELECT

 external_identification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          document_file
          product_definition

 identification_item - EXTENSIBLE SELECT
          document_file

 versionable_item - EXTENSIBLE SELECT
          document_file