LegacyGhostCellsGenerator: bring back into ParaView via plugin
Revive the LegacyGhostCellsGenerator. This filter was removed in ParaView 5.11.0, but the parallel version's MPI usage pattern does not overwhelm some MPI resources on newer HPCs like the diy2-based vtkGhostCellsGenerator can. Hence, we are bringing it back into ParaView for 5.12.1 as a plugin of the same name.
Backport: release
Edited by Cory Quammen