Concept definition

template<typename EvaluatorType>
concept mgis::function::ST2toT2EvaluatorConcept = 
      (ST2toT21DEvaluatorConcept<EvaluatorType>) ||
      (ST2toT22DEvaluatorConcept<EvaluatorType>) ||
      (ST2toT23DEvaluatorConcept<EvaluatorType>)