kwctl allows scaffold of AdmissionPolicies that target cluster-wide resources

[kravciak]

Current Behavior

There are 2 types of policies: ClusterAdmissionPolicy and AdmissionPolicy.

All of our policies can be defined both as ClusterAdmissionPolicy and AdmissionPolicy. However, policies targeting cluster-wide resources are going to be evaluated only when deployed as ClusterAdmissionPolicy.
If I deploy a policy inspecting cluster-wide resources (like Namespace, PersistentVolume,...) as an AdmissionPolicy, the policy will never be invoked.

Expected Behavior

• kwctl should have knowledge whether an official Kubernetes types is namespaced or not. When the user tries to scaffold a AdmissionPolicy and the policy is targeting a cluster-wide resource, the program should exit with an error
• For policies targeting Custom Resource Definitions there's no way for kwctl to know whether this is a cluster wide resource or not. In this case, when scaffolding a AdmissionPolicy, kwctl should print a warning message. It's left to the user to figure out whether the CRD is cluster-wide or namespaced