Document and contextualise kube-bench results for KKP

[embik]

We should look into publishing results for https://github.com/aquasecurity/kube-bench on a stock KKP user cluster to our docs. Some tests might also be false-negatives, so we need to document why we believe those are not valid, so users running kube-bench on their own can understand the results they are getting.

I think it would be best to store the results in some data format (e.g. JSON, maybe kube-bench supports that as output), enrich it with context and render it into a document nicely. That way, we might be able to update it nicely.

[embik]

It's also possible to provide a custom kube-bench configuration that would exclude the checks not applying to KKP. As long as we publicly document why we are excluding them, it should be fine.