Custom resources list for --feature-gates=ProxyAllNamespaced=true.

[anatolychernov]

Describe the feature

According to issue 303, capsule-proxy provides the ability to list all resources within a user’s tenants when the ProxyAllNamespaced feature flag is enabled, e.g. kubectl get pods --all-namespaces

It would be great if we could manage the list of resources where a user can use the cluster scope flag --all-namespaces, e.g.

ProxyAllNamespacedResourcesList:
  - pods/v1
  - secrets/v1
  - configmaps/v1

Some operators (like the Operator Lifecycle Manager) strictly control their resource labels, and if the capsule-proxy tries to add its own label, a conflict between the capsule-proxy and the operator may occur.

If you think this idea is good, I can try to prepare a merge request.

What would the new user story look like?

If ProxyAllNamespacedResourcesList is not empty, the user can apply the --all-namespaces flag only to the resources defined in ProxyAllNamespacedResourcesList.
Otherwise, if ProxyAllNamespacedResourcesList is empty, the user can still list all types of resources under their tenants using the --all-namespaces flag.

Expected behavior

A clear and concise description of what you expect to happen.