how to avoid shared-library conflict trouble

[KrisThielemans]

We will have more and more trouble with shared libraries. Most importantly this will hit is more with the HDF5 library. On linux, we have system HDF5 libraries, some distributed with Python, some with MATLAB. Ideally we just use the one that STIR was compiled with.

Some links

https://gitlab.kitware.com/cmake/community/-/wikis/doc/cmake/RPATH-handling

https://cmake.org/cmake/help/latest/manual/cmake-packages.7.html#creating-relocatable-packages