[DEPR-2U] [Discovery] How do we build devstack images post devstack-deprecation?

[dianakhuang]

Original DEPR:

• [DEPR]: Dockerfiles and Docker images openedx/public-engineering#263

I believe devstack images are built in the repositories themselves as a GitHub action. Part of this deprecation will be to remove those actions. We will probably want to build these images in the devstack repo if that's the case.

Acceptance Criteria

• alternative plan to build images through devstack repo's GitHub actions
• move edx-platform to using it

Implementation Notes

• verify that we actually know how these images are getting built
• find out if these images are used as the base for the production images used for k8s deploys

[robrap]

@dianakhuang: Another that needs a due date.