Control REST resource generation to allow entities to be sent in response to POST request

The generated REST resources always issue a HTTP 201 Response with a Location header in response to a HTTP POST. Some clients expect the response to contain an entity representation of the newly created resource. Therefore, we should allow users to control whether they want the entity to feature in the response.

This would require:

• the method be annotated with @Produces with the mediatype being the chosen resource representation.
• the entity() method be invoked to populate the entity in the response.