[feature] Add image build vars to backend Makefiles

[gmfrasca]

Feature Area

/area backend

What feature would you like to see?

I would like to be able to simply run make image_XYZ while doing development work, which would use my preferred image build executable and publish to an image tag that I have defined; right now the images built are hardcoded to use docker, and publish to a hardcoded name and tag.

What is the use case or pain point?

Backend make image_XYZ commands are hardcoded to use the docker executable, and write to a hardcoded image name (w/ no tag, therefore always defaulting to latest). This also means if developers have multiple 'branches' of work ongoing they must remember to re-tag previously built images or risk overwriting old ones. It would be nice if the Makefile included a mechanism to override this, as a small QoL improvement.

Is there a workaround currently?

To work on multiple parallel work items, developers need to either re-tag built images or manually run image build commands which is a bit of an annoyance.

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[rimolive]

/assign @gmfrasca

[gmfrasca]

Fixed by #10725