back port patch to vtkPoints

[burlen]

VTK made vtkPoints a first class dataset. this looks fairly straight forward and is an improvement over PolyData and UnstructuredGrid for particle data. See convo in #129

This is the commit
https://gitlab.kitware.com/vtk/vtk/-/tree/57e4caaaee0f5bfe6d008b35321209c19375f2b0
and some discussion on discourse
https://discourse.vtk.org/t/vtk-polydata-dataset-with-points-only/4293