This fix tries to improve the display of `docker service ls` and adds `--format` flag to `docker service ls`. In addition to `--format` flag, several other improvement: 1. Updates `docker stacks service`. 2. Adds `servicesFormat` to config file. Related docs has been updated. Signed-off-by: Yong Tang <yong.tang.github@outlook.com> Upstream-commit: 000f0403d9084e8da427bafac3b594a822b3c386 Component: engine