Fix an issue that snmp will fail to start if mgmt ip is not specified in minigraph (e.g. default graph in oneimage where mgmt ip is from DHCP)
Add a sonic-config-engine to help generate config file based on minigraph and other data on runtime. Modify fpm, teamd, lldp, snmp, and platform-monitor docker to use sonic-config-engine to generate config in docker upon load.