Resolve "Move references to GUDMAP/RBK"

Allow workflow to download references from datahub. Also started using gudmaprbk dockerhub (containers autobuilt).

PR checklist

• This comment contains a description of changes (with reason)
• If you've fixed a bug or added code that should be tested, add tests!
• Documentation in docs is updated
• Replace dag.png with the most recent CI pipleine integrated_pe artifact
• CHANGELOG.md is updated
• README.md is updated
• [ ] LICENSE.md is updated with new contributors
• [ ] Docker images moved to production release and changed in pipeline
• Docker images used in the CI unit tests match those used in pipeline

• Close issue
  Closes #23 (closed)

/cc @ghenry @venkat.malladi