Support multiplanes for clip filter in vtkh

In vtkh, the clip filter use multi-planes here (https://github.com/Alpine-DAV/ascent/blob/develop/src/libs/vtkh/filters/Clip.cpp#L334), it uses an extra worklet to compute the distance from a point to each plane and return maximal distance (https://github.com/Alpine-DAV/ascent/blob/develop/src/libs/vtkh/filters/Clip.cpp#L70). I am wondering what is the proper way to support the clip filter with multi-planes in vtkm. Maybe adding a vtkm::MultiPlans here (https://gitlab.kitware.com/vtk/vtk-m/-/blob/master/vtkm/ImplicitFunction.h#L750), and make it works with the ClipWithImplicitFunction, how do you think about it? @kmorel @ollielo, thanks for the help!