Add Istio Ambient Mode

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: add-ambient-mode-namespace
  annotations:
    policies.kyverno.io/title: Add Istio Ambient Mode
    policies.kyverno.io/category: Istio
    policies.kyverno.io/severity: medium
    kyverno.io/kyverno-version: 1.8.0
    policies.kyverno.io/minversion: 1.6.0
    kyverno.io/kubernetes-version: "1.24"
    policies.kyverno.io/subject: Namespace
    policies.kyverno.io/description: In order for Istio to include namespaces in ambient mode, the label `istio.io/dataplane-mode`  must be set to `ambient`. As an alternative to rejecting Namespace definitions which don't already  contain this label, it can be added automatically. This policy adds the label `istio.io/dataplane-mode` set to `ambient` for all new Namespaces.
spec:
  rules:
    - name: add-ambient-mode-enabled
      match:
        any:
          - resources:
              kinds:
                - Namespace
      exclude:
        any:
          - resources:
              names:
                - kube-system
                - istio-system
      mutate:
        patchStrategicMerge:
          metadata:
            labels:
              istio.io/dataplane-mode: ambient