sci-libs/med: merge libmed into med

sci-libs/med: merge libmed into med

* Merge sci-libs/libmed into sci-libs/med, to resolve redundancy.
* Changed to use autotools instead of cmake, as sci-libs/gmsh does not
  build against the cmake built variant.
* Remove mpi USE flag, as there's no option to disable mpi support when
  using autotools to build the package.

Closes: https://bugs.gentoo.org/693146
Package-Manager: Portage-2.3.74, Repoman-2.3.17
Signed-off-by: Bernd Waibel <waebbl@gmail.com>
Signed-off-by: Matthias Maier <tamiko@gentoo.org>