Add a pqProxy for the PV SMTK model representation.
Hook up the representation's SMTK selection manager so that when the selection is changed a redraw is requested.
This proxy is also intended to subsume the duties of vtkSMSMTKModelRepresentationProxy and to inform (via a request to the SMTK resource manager) the server-side representation of the server-side SMTK selection to use for rendering.
This class should eventually move to
smtk/extension/paraview/appcomponents but cannot until the other
classes move (to avoid cyclic dependencies).