Pre-build acceptance test image for pipeline

At the moment we do quite a few steps on top of the golang image in our acceptance test jobs to make it ready for them, like:

1. Installing docker + docker-compose
2. Installing Terraform
3. Pulling images

It would be nice if we can pre-build an image and push to our registry to re-use in the jobs. At least point (1) and (2) - I'm not sure if (3) is really possible ... but worth a try 😄