Draft: Update LUMI installation instructions
Update siteconfig according to !1643 (merged) and add build scripts and modules.
Tests on d5997258:
- GPU build:
pytest --pyargs gpaw -v -m gpu
passes with 1 CPU + 1 GPU - CPU build:
pytest --pyargs gpaw -v
passes with 1, 2, 4, 8 CPUs
Edited by Tuomas Rossi