* [service] Restart SwSS Docker container if orchagent exits unexpectedly
* [dhcp_relay] Use STATE_DB to determine whether interfaces are ready
* Supervisor now autorestarts rsyslogd upon unexpected exit
* Add other critical processes to event listener
* Make supervisor-proc-exit-listener script global, have it read from 'critical_processes' file inside container
* Add SwSS to 'WantedBy=' option of services which should be started along with SwSS
* Add docker-dhcp-relay/Dockerfile to .gitignore
* Add isc-dhcp-relay .deb package to image build process, along with my Option 82 patch
* Install custom isc-dhcp-relay in dhcp_relay docker
* Install isc-dhcp-relay build dependencies in sonic-slave Docker container
* Copy the built .deb package to the destination directory
* Add dependencies for isc-dhcp-relay
* Change Option 82 string to '<hostname>:<portname>'
* Install dependencies of .deb files implicitly in Dockerfile
* Remove unused line
* Remove unnecessary space
* [docker-config-engine]: introduce docker sonic config engine
sonic config engine provide the sonic configure engine for all sonic
dockers that rely on the engine to generate runtime configuration.
