Add MegaRAID controller/array health monitoring to SNMP agent checks.

With vendor provided appliances (which are just Linux servers) it's often not possible or permitted to install 3rd party software like the checkmk agent, or MegaCLI. But SNMP is usually running, and LSI software is often running that provides OS visibility to the hardware RAID controller. Unfortunately, Checkmk just doesn't look for and monitor this available info.

Top OID: .1.3.6.1.4.1.3582
MIB: LSI-MegaRAID-SAS-MIB

A few interesting values:
LSI-MegaRAID-SAS-MIB::alarmState.0
LSI-MegaRAID-SAS-MIB::vdDegradedCount.0
LSI-MegaRAID-SAS-MIB::vdOfflineCount.0
LSI-MegaRAID-SAS-MIB::pdDiskFailedCount.0

I believe this would be a valuable addition to Checkmk.