* [cfggen] Support reading from and writing to configdb
* [bgp] Move bgp_admin_state to configdb, support dynamic admin state change
* [sonic-utilities] Adapt configDB for admin status, support config save and config load
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.
