Add XOS SNMP v3 plugin

[0xlord]

[Added] modified Extreme OS plugins for SNMP v3 usage
[Fix] Slightly edited output for teminal usage

[binfalse]

Thanks a lot @0xlord !
But wouldn't it be better to merge the two versions? The code for v3 and v2 just differs in a few lines, much of the code is the same...

[0xlord]

Hi @binfalse,

thanks alot. The moment I sent the pr I've thought about it too. I don't have the time to rewrite the script for that, but I will look into it hopefully soon!