This adds a target to install MiniEM as well as the needed input files

Files are installed to:
$CMAKE_INSTALL_PREFIX/example/PanzerMiniEM/

The prior path is chosen, because installing to 'bin/' is unusual when
the binary has required input files. See the PR for this issue for
discussion on that.

Optionally, set:
PanzerMiniEM_INSTALL_PREFIX

To override the install location for MiniEM

Closes: #5083