Migrate the installer to python
Currently the spack_setup.sh
builds the toolchains, if we migrate this to a python script, we will have the following benefits:
- we might be able to run the installer in macsos
- better control over which modules are created and in which order
- install custom variants for, e.g. of openmpi for non-HPC machines
- detect the system compiler used, and modify the spack overlays accordingly