Actually run go build in docker (cd&rollout)

[sven-urbanski-freiheit-com]

• Removes the "backend" docker container (it was redundant).
• cd & rollout services now actually build go code in docker. Before, the binary was build on the host, and then only copied into the docker image.

[hannesg]

I think the name swissknife is really bad. I sounds like "does everything for that we don't have a name". Why not keep builder?