- Add Capella
- Add links to hardware overview for all mentioned cluster

- Remove outdated note on SSD storage
- Refine note on node-local storage

- Address reader/user

Co-authored-by: Jan Frenzel <jan.frenzel@tu-dresden.de>

Co-authored-by: Jan Frenzel <jan.frenzel@tu-dresden.de>

Co-authored-by: Jan Frenzel <jan.frenzel@tu-dresden.de>

Co-authored-by: Jan Frenzel <jan.frenzel@tu-dresden.de>

All `Python` modules now export `PIP_REQUIRE_VIRTUALENV=true`.
This causes an error when users try to use `pip install` without an
active virtualenv.
This also avoids admins accidentally installing/changing Python packages
in the global module.

and romeo