math/arpack-ng: Flavorize on MPI implementation

Positives are that now *-mpich, *-openmpi, *-nompi
packages would be all available.

Negative is that they conflict with each other.
The files need to have the unique suffix.

All flavors are equal, there is no obvious default
among them, so suffixes were added to all of them
to make it clear which implementation is installed.

PR: 293569
Requested by: Steve Kargl <kargl@FreeBSD.org>