Upstream mirrors kubernetes types as Resourses, NodeSelector, Labels or IntOrString for the values_types.proto.

We could use the available types in the buf.build registry instead (cf. https://buf.build/k8s/api).

Acceptance criteria

• Get rid of mirrored types (eg. https://github.com/istio/istio/blob/master/operator/pkg/apis/istio/v1alpha1/values_types.proto#L220-L230)