2020-11-08: initial release 2021-02-25: rewrite for cmk 2.0 2021-09-11: added WATO, cleanup 2022-10-23: fixed warning on upgrade "non-empty params vanished" for discovery_chassis and discovery_sgms 2022-11-17: added woraround for wrong snmp data for grade/maxgrade in R81.x 2022-11-30: WATO: fixed CheckParameterRulespecWithoutItem (from CheckParameterRulespecWithItem)