Expose ODataJPAResponseBuilder for External Usage

At times it is required to write an own OData - JPA Processor instead of using the default OData - JPA processor - org.apache.olingo.odata2.jpa.processor.core.ODataJPAProcessorDefault.

One could implement a OData JPA processor by extending the org.apache.olingo.odata2.jpa.processor.api.ODataJPAProcessor class. The class encapsulates an instance for processing OData request (org.apache.olingo.odata2.jpa.processor.api.access.JPAProcessor).

However to build an OData response from a JPA Entity for a given OData request there is no such instance encapsulated.

Hence extend ODataJPAProcessor class to encapsulate a OData JPA Response builder which can be used by the subclasses for building OData Responses from JPA Entity.