Kubernetes-style API reference

**Describe the problem/challenge you have**
The API references right now are a big YAML document with comments. For issues like https://github.com/vmware-tanzu/carvel-kapp-controller/issues/415 it would be nice if we had a way to go into more detail with actual links, ala https://kubernetes.io/docs/reference/kubernetes-api/workload-resources/deployment-v1/

**Describe the solution you'd like**
Investigate what we can do to create better API docs. Big bonus if these are generated from our code rather than hand-written in the docs repo.

**Anything else you would like to add:**
- https://kubernetes.io/docs/reference/kubernetes-api
- https://cert-manager.io/docs/reference/api-docs/
- https://knative.dev/docs/reference/api/serving-api/

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