This is a follow-up of sonic-snmpagent PR 92
Now that licensing issues have been solved FRR is distributed with SNMP
support compiled-in. This PR adds the last bits of configuration to get
the frr-snmp debian packages added to the docker container and the
config bits to enable the snmp module in FRR
This PR brings the functionality of being able to poll bgpd for routes
and peer status.
Signed-off-by: Michel Moriniaux <m.moriniaux@criteo.com>