GH Build and Publish image Action

[ciroque]

Proposed changes

There should be a GitHub Action that builds the Docker image and publishes it to the GitHub Container Registry (GHCR).
Acceptance Criteria:

• Builds main only after successful rebase and build / test Action
• Pushes to GHCR with tags: latest, commit hash, and build number
• Signs the image

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md and CHANGELOG.md)