docker regsitry. This version has the API to call regsitry GC with jobservice
secret. Seprates it into a standalone container as do not want to invoke two
processes in one container.
It needs to mount the registry storage into this container in order to do GC,
and needs to copy the registry binary into it.
The following are done to avoid travis-ci failing due to too much log
size.
1) Update Makefile and scripts to make go build less verbose.
2) Make tdnf less verbose
This change involves using non-root user to run the process of the
docker images. Also made update in Dockerfile to make the containers
support "read-only" and introduce "HEALTHCHECK". Note the "read-only"
options are not enabled in docker-compose, to cover the very corner
case when user wants to update the container filesystem manually.
Remove read only option from docker-compose template by default
