This also adds a new Dockerfile for a e2e-test-image, as the old
image was hosted on our private registry. By having the image located
near the code, we don't have to rely on images on external registries.
As of version 1.1.2 of Nomad, the CLI monitors job deployments by
default until they are finished. Thus our custom job deployment
watcher script is not required anymore.
We previously didn't really had any structure in our project apart
from creating a new folder for each package in our project root.
Now that we have accumulated some packages, we use the well-known
Golang project layout in order to clearly communicate our intent
with packages. See https://github.com/golang-standards/project-layout
