* Add OS detection for Greenbone appliances
They don't expose anything fancy over SNMP, but this makes them
display interface names correctly. Under the hood they're unix-y.
Greenbone logo is from the AGPLv3 gsa, which is GPL compatible:
https://github.com/greenbone/gsa/blob/master/gsa/public/img/greenbone.svg
The mib is included for completeness, but it doesn't expose any
graphable values.
* Fix the vendor's logo
