investigate convergence with Application SIG work

[joel-bluedata]

https://github.com/kubernetes-sigs/application

The Application CR they're developing isn't a 1-to-1 match with the concepts/responsiblities of a kdcluster CR, but there is definite overlap. If this gets uptake -- and so i.e. there would be an application controller running in a K8s cluster and various things paying attention to Application CRs -- we would likely want to see if we can play in that ecosystem with kdclusters too.

There are several ways we could tackle that. For example, have an Application CR be owned by a kdcluster CR or vice-versa, and get rid of any redundant info from kdcluster. Not sure yet.