GitLab

* Add multi-arch support for container images

Currently we have a arch-specific binary that gets installed on an amd64
container. This change ensures that the container image matches the
arch-specific binary.

Using alpine archictecture-specific images as  mentioned under
https://hub.docker.com/_/alpine

To support architectures different from host architecture, this uses
qemu-static.

* Lint Dockerfile

Use COPY instead of ADD
https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#add-or-copy