The class has been removed as of VTK 9.3.0.

- closes #18687

This reverts commit 227e838a.

Adresses #20004

The filter vtkProbeLineFilter has been updated so add/update related proxies :
 - ProbeCustomLines act as the Plot Over Line filter but allows for multiple lines and polylines using a 2nd input.
 - ProbeLine has been redefined to follow the new API.

Fixes #20802

The ghost cells generator backend was changed in July 2021.
The legacy backend is put back for 5.10, named Legacy Ghost Cells Generator,
in case there are bugs in the new backend, so users can go back to
previous version if necessary.

The ghost cells generator, which used to only work for
vtkUnstructuredGrid, is now replaced by the new ghost cells generator
that works on vtkImageData, vtkRectilinearGrid, vtkStructuredGrid,
vtkUnstructuredGrid, and any vtkMultiBlockDataSet,
vtkPartitionedDataSet, and vtkPartitionedDataSetCollection composed of
the latter base types.

The old backend is being removed.

The new backend uses the new filter vtkProbeLineFilter.
The former backend can still be used and is deprecated in 5.10.
A test has been added to ensure that old state files still work.

Fixes #20297.

Making TestValidateProxies pass for CORE + Python + MPI build. Moving
proxy definitions around as needed.

Splitting server manager xmls to ensure that definitions go together
with appropriate modules.