feat: OPA build from source

[fhennig]

Description

We tested that the smoke test runs :+1:

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
- [ ] Does your change affect an SBOM? Make sure to update all SBOMs
- [ ] 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: ```shell bake --product --image-version kind load docker-image --name= ``` See the output of `bake` to retrieve the image tag for ``.

[fhennig]

@lfrancke I think your stuff was done too, if not, create a ticket for it!