Do not install GNU Make and pkg-config support files

Default Geant4 build installs helper files to be able to use Geant4 from simple GNU Makefiles or via pkg-config. The GNU Make support is responsible for creating a symlink pointing to a parent directory (with something like ln -s .. Linux-g++) which causes problems in our binary artifacts as we dereference symlinks when packaging.

Since we do not need support for GNU Makefiles of pkg-config in LHCb builds of Geant4, this MR disables then effectively removing the problematic symlink.

Closes #5 (closed)