adding geo-sciences/fullprof-bin to the sci-overlay

As wished in https://bugs.gentoo.org/show_bug.cgi?id=443512 here is the according pull request.

I think adding the fullprof directory to the path is better than adding 25 symlinks (as of now) to /opt/bin. Also upstream might add more binaries and then one might forget to add another symlink to the ebuild increasing the maintenance costs.