Extensible select and enumeration types

and their elements in schema Design_management_arm taking into account BASED_ON types


 activity_item - EXTENSIBLE GENERIC_ENTITY SELECT

 affected_item_select - EXTENSIBLE SELECT

 approval_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Frozen_assignment

 date_or_date_time_item - EXTENSIBLE SELECT

 managed_design_object - EXTENSIBLE GENERIC_ENTITY SELECT
          Product_view_definition