[Observium] Feature request: OpenBSD CARP and pf

Hi there!

I would like to request CARP-MIB and PF-MIB support in Observium.

Most importantly show if the CARP interfaces are master or backup. So we can get alerted. Maybe show it in the same way as Cisco ASA Active/Passive or some other better suited as you can have an arbitrary amount of CARP interfaces. And then the ability to graph the statistics from PF-MIB.

The MIBs for reference: https://github.com/openbsd/src/tree/master/share/snmp Not sure if this is a lot of work or not though, hope some of it is easy enough :)