* Include the response type in ProducesResponseType for client errors
* Refactor ActualApiResponseMetadata discovery in to a separate more manageable type
* Annotate action result ctors and helper methods that specify the "object" value with attribute
* Modify the discovery of parameters to match ActionResultObjectValueAttribute and ActionResultStatusCodeAttribute by name
to allow users to write and annotate custom helper methods and action results, a la NotNullAttribute.
Fixes#8345
