cliutil: export data about running cluster

[sam-heilbron]

Description

Create a utility to export data about a running cluster.

Blocked By

• test/kube: Introduce framework #9358

Context

I broke this off from #9327. The idea is that we know we need some utility to export data from a cluster. We hope to use this in tests and eventually expose it in our CLI.

I decided to add this code in a shared place, but only call it from tests for now. This way we can keep iterating on it before we decide what to expose in our CLI to useres.

Interesting decisions

Testing steps

• TODO

Notes for reviewers

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works