Cleanup common non-namespaced resources (Closes #4747)

[LoniasGR]

Summary

This MR adds some common non-namespaced APIs to be removed when doing a microk8s reset. I also refactored the code a bit to be more consistent and fixed the help message for destroy storage.

Closes #4747
References #3243 #4297

Changes

I added the removal of CRDs to a function and created a function for the rest of the non-namespaced APIs.

Testing

I ran the following steps:

1. Setup microk8s cluster.
2. Install ingress-nginx-controller as described here.

     helm upgrade --install ingress-nginx ingress-nginx \
        --repo https://kubernetes.github.io/ingress-nginx \
       --namespace ingress-nginx --create-namespace

3. Run microk8s reset.
4. Everything was removed.

Possible Regressions

Checklist

• Read the contributions page.
• Submitted the CLA form, if you are a first time contributor.
• The introduced changes are covered by unit and/or integration tests.

Notes