XCF-1891 Implement Call Statistics into MRTG implementation

Andrei:
I had a quick look at the patch. I think I can apply it after rebase (see
attached), but I am not sure it that would be correct.

After splitting SNMP and MRTG configuration we assume that SNMP is run on all
servers in the cluster while MRTG only on the primary server (the one where
sipXconfig is running). Your patch exposes call statistics through SNMP, but
call statistics is internally provided by call resolver which only runs on a
primary server.

I rebased your patch and move snmp initialization to a newly created
sipx-snmp-init, but I am not sure if that's the right thing to do. Ideally
sipXagentX would be responsible for configuring SNMP agent, right?

Do you have any suggestions on how to proceed?

I was thinking that one possible solution would be asking every service to
install its own part of snmp configuration. If snmpd does not support natively
reading the configuration from multiple files we could add the functionality
that assembles a single file (since we already have sipxconfig-snmp module that
changes that file). That would allow sipXagentX to install its own MIBs only on
the primary server.

What do you think?
D.