feat: Use Github Actions to build and publish docker images to GHCR

[irvingpop]

Which problem is this PR solving?

• As of April 1st, 2025 Dockerhub will further clamp down on pull rate limits for unauthenticated users, which might make things difficult for our customers with larger Refinery deployments.
• In order to improve the resilience of customer deployments, let's dual-publish Refinery images to Github Container Registry (GHCR)
• One challenge with extending our CircleCI pipeline to do this is that external auth to GHCR is limited to PATs only

Short description of the changes

• This PR adds a Github Actions native workflow, which builds and publishes a Docker container exactly the same way as build-docker.sh and CircleCI, but with a greatly simplified configuration.

I tested this out in a forked repo, with the results here: https://github.com/irvingpop/refinery/pkgs/container/refinery

[TylerHelmuth]

@JamieDanielson had an idea that instead of building a new image, can this action be dependent on the cirlceci job completing and then pull the image and re-push it?

[JamieDanielson]

Also we'd want/need this to happen after a successful build and publish. So it looks like you can change the trigger to be on release publish

on:
  release:
    types: [published]

[irvingpop]

Oh neat! updated.

[verythorough]

I'm sure y'all have already thought of this, but I wanted to note that once we have this option, we'll probably want to add it to the docs anywhere we mention using Docker Hub.