Re-fix resource linking

Created by: OPNA2608

Some corrections to #739:

1. CMAKE_INSTALL_RPATH is concatenated from CMAKE_INSTALL_PREFIX variable and /lib. This should instead use the CMAKE_INSTALL_FULL_LIBDIR variable.
2. Re-apply the resource linking fixes from #798, which seem to have been unintentionally dropped in a merge conflict resolve. (recap: Use CMAKE_INSTALL_FULL_DATAROOTDIR instead of hardcoding /usr/share, detect & replace bad symlinks)

1. is untested but seems correct to me. 2. was previously merged, I've just re-applied the changes with some minimal changes.

Fixes #1298 (closed).