arm64 support in docker image

I'm texting CodeX Docs in Docker, and was unable to get it up and running on my arm based server due to missing architecture support. I have successfully spun it up on a x86 host, however arm support would simplify the setup.

Not sure of the effort to include an arm build in the docker registry for the project, so if this is an unreasonable request let me know.

The issue points to the Docker image and its registry publication, but names no files or tests. Start by locating the image build and publication configuration, then check how architecture support is currently defined. Done means an arm64 image is published and the application starts successfully on an arm-based server.

Written by the indexing model from the issue text.