CLI should build and push with Docker

[codeblooded]

The CLI should be able to build, tag and push using Docker. The best way would be to use the library that the Docker CLI relies on: https://github.com/moby/moby/tree/master/client. This would be tested. A hacky alternative for a quick prototype is to wrap the docker CLI using the os/exec package.

[codeblooded]

Some good news: an experiment is now working with it building through go :)