Bring back 'kubernetes' for Kubernetes resource types

The current naming scheme for Kubernetes extensible resources leads to some non-obvious cases. You might see a name like:

- `core/Secret@v1`
- `apps/Deployment@v1`
- `rbac.authorization.k8s.io/ClusterRoleBinding@v1`

It can be hard to tell visually that the first two of these have anything to do with Kubernetes because the names are so generic.

We could solve this by naming the built-in groups like `kubernetes.core` or `kubernetes.apps` instead of just one word. `rbac.authorization.k8s.io` feels obvious enough already

No files, tests, or entry points are named. Start by tracing how built-in Kubernetes resource groups are assigned their names, then determine where the naming convention is defined. Done means built-in groups use the proposed Kubernetes-prefixed names while the existing RBAC group remains unchanged, with relevant tests updated or added.

Written by the indexing model from the issue text.