2021-02-25: rewrite for CMK 2.x
            added warning/critical is chassis grade not equeal maxGrade
2021-09-10: rewrite parse function
2021-09-11: added WATO, cleanup
2022-10-23: fixed warning on upgrade "non-empty params vanished" for discovery_chassis and discovery_sgms
2023-05-29: moved gui files to ~/local/lib/check_mk/gui/plugins/...