Extensible select and enumeration types

and their elements in schema State_definition_arm taking into account BASED_ON types


 activity_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Applied_state_definition_assignment

 classification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          Applied_state_definition_assignment
          State_definition
          State_definition_relationship

 identification_item - EXTENSIBLE SELECT
          State_definition
          State_definition_relationship

 state_definition_of_item - EXTENSIBLE GENERIC_ENTITY SELECT