Add docker client and awcli into DjangoNode agent

[egregors]

I would like to find a way to run Docker commands inside the agents.
We shouldn't use https://github.com/jpetazzo/dind
Instead I'll try to mount docker socket from host to agent container, like this: http://jpetazzo.github.io/2015/09/03/do-not-use-docker-in-docker-for-ci/

It is useful for building images by agents and pushing them to Docker Registry.

And, I'll add awscli for pushing images in Amazon ECG