Implement more config template for docker image

the template is commented out today: https://github.com/indeedeng/iwf/blob/main/config/config_template.yaml

See example of how to use it https://github.com/cadence-oss/cadence-notification/blob/master/Dockerfile#L26

It's missing Cadence and other setup, also need to use templating command to converting the value from template into config files