Introduce build inside the docker

[onorua]

This should simplify adoption by the community, and may save couple of hours for new users who would like to just try the tool without additional efforts.

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[onorua]

I signed it!

[googlebot]

CLAs look good, thanks!

[ibakirov]

I suggest to use FROM debian:jessie rather than FROM ubuntu:* in this dockerfile, to be far away from any Canonical's IP Policy speculations...

By the way, Google CLAs also signed!

[onorua]

If that the reason to don't merge - I'll update the base image. Many projects use Ubuntu as base image which makes it better candidate to prevent downloading of the underlying layers.

[bwahn]

If seesaw run in docker, It may be would better add some command and explanation. For example, It may use like "$ docker run -d seesaw". @onorua Do you have some idea?

[ibakirov]

$ docker run -d seesaw can be done after Dockerfile accepted and official image on Hub published

[onorua]

I do not run seesaw in the docker, I do build of the packages without necessary installing anything on your host. That is why I call it "hack" the same way as kubernetes has it, if you want to hack around, you need to be able to build it. But I can work on running the seesaw inside the docker as well, if there is a need. But this most probably be another pull request.