Small fixes + OS definitions changes

Fixes/Changes in this patch:

Escape more output in devices page
Change more $_GET/$_POST to $vars (in billing)
Add os definition for sensatronics devices
Put drac OS in management type (like hpilo)
Add current/voltage to liebert os
Add MIB to palo alto (panos) definition
Added mib blacklist for entity and lsi-megaraid on DSM os
Added unix group to opengear os (detects processor)
Change type from network to management on opengear os
Moved panos sessions graph from polling/os to polling/graph
In fabos polling, fetch hardware & serial from entPhysical
In powerconnect-radlan polling get hardware using productIdentificationDescription