add page for training material
- HPC2N: website, YT videos
- HPC NRW: website, YT videos
- NHR@FAU: website, YT videos
- MPCDF: website, upcoming courses and presentation archive, documentation
- LRZ: website, upcoming courses, lecture notes
- PRACE: website, Tutorials
- ECP: website, YT videos
- ENCCS: website, training material