chore: move product versions into product directory in preparation for individual product build workflows

[NickLarsenNZ]

Description

• Update image-tools to 0.0.8 (to support importing python modules via conf.py)
• Move each products version list to a file in the product directory, and import it in the main configuration.
  This will allow us to only build the relevant images based on the change paths (future PR).

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

- [ ] Changes are OpenShift compatible
- [ ] All added packages (via microdnf or otherwise) have a comment on why they are added
- [ ] Things not downloaded from Red Hat repositories should be mirrored in the Stackable repository and downloaded from there
- [ ] All packages should have (if available) signatures/hashes verified
- [ ] Add an entry to the CHANGELOG.md file
- [ ] Integration tests ran successfully

TIP: Running integration tests with a new product image

The image can be built and uploaded to the kind cluster with the following commands:

bake --product <product> --image-version <stackable-image-version>
kind load docker-image <image-tagged-with-the-major-version> --name=<name-of-your-test-cluster>

See the output of bake to retrieve the image tag for <image-tagged-with-the-major-version>.

[Maleware]

I've compared a few versions with the original conf.py and haven't find any problems yet.

LGTM - thank you!