Extensible select and enumeration types

and their elements in schema REQUIRED_RESOURCE_XIM taking into account BASED_ON types


 classification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          required_resource
          required_resource_assignment
          required_resource_relationship
          resource_item
          resource_item_assignment
          resource_item_relationship

 required_resource_item - EXTENSIBLE GENERIC_ENTITY SELECT

 resource_assignment_item - EXTENSIBLE GENERIC_ENTITY SELECT

 resource_item_select - EXTENSIBLE GENERIC_ENTITY SELECT