Deprecating pqDisplayPolicy for the most part.
vtkSMParaViewPipelineControllerWithRendering is now the class that
manages all the logic in pqDisplayPolicy instead.

Updating vtkSMViewProxy API to add CanDisplayData() which is needed for
vtkSMParaViewPipelineControllerWithRendering to work correctly.

Fixed usage of pqDisplayPolicy is core ParaView. Plugins and examples
still need to be updated.

Change-Id: I4188acaceedde2e0fe8e927e142b9a62615515f9