Attention: Generic SNMP Device Extension duplicates interface metrics

[r_weber]

During an analysis I noticed that the current Generic SNMP Extension duplicates some interface metrics.

I found that these metrics are created/ingested twice, which can be a significant cost driver if you have lots of devices.

if.lastchange
if.out.errors.count
if.out.discards.count
if.in.errors.count
if.in.discards.count

Generally the extension is very cost-intensive for what benefits it actually brings. IMO it should be cost optimized or at least allow the user to e.g. change the time granularity of interface/device metrics...e.g. from 1min resolution to 5 min resolution.