Adding Docker build step to Spiderfire.

[coillteoir]

Building docker images is an important part of deploying server-side applications. It would benefit this project if a docker build is maintained.

Why?

Using a spiderfire base image would make it easier for developers to deploy their applications. It also means that when a package manager is implemented, users can bundle their applications into docker images.

Proposed Implementation

A Dockerfile would initially be placed at the top of the repository. If there's demand for multiple distros/architectures then a Docker directory can be made with the respective builds.

A justfile directive will also be added that allows you to run just docker-build to build your image. A docker push directive may also be implemented as well.

Finally, the CI will be updated with a docker build directive.