Dockerize

[nandanrao]

As a developer, when I push a new tag to the master branch, I want a Docker container of the application built and available in a public container repository.

Decisions:

1. Decide on container registry (DockerHub? GH Container Registry? Run our own Harbor/Quay?Trow?)
2. Decide on automated build tool (Github Actions? Run our own Jenkins/GoCD/Drone?)

I vote that, for now, we just run on GH Actions with GH Container Registry. It's cool to run our own everything, but as long as we're using hosted Git on GH, we might as well do everything there, imho.

Recommended Steps:

1. Create Dockerfile, ensure build works locally and app works.
2. Setup in GH Actions and ensure container is publicly accessible.