ClipWithField: Split instanciations of the class
Fixes: #578 (closed)
This MR attempts to reduce the memory usage of the compilation of
VTKm filters, specifically
ClipWithField, although through this optimization other filters compilation overhead can be incidentally improved.
This parametrize the files ClipWithField.hxx and the new implementation files
pyexpander to concisely instantiate in those specific units the class templates instances of