science/paraview: upgrade to 5.12.0
Release notes at <https://www.kitware.com/paraview-5-12-0-release-notes/>.
Documentation has been removed: not yet supported with Qt6.
science/paraview: upgrade to v5.10.1
- Use external libraries when possible;
- Take maintainership.
Unfortunately is not passible to produce a working package with MPI
enabled, because net/py-mpi4py is compiled against openmpi by default,
and other ports against mpich. It is possible to compile it, but check
carefully that only one MPI is installed!