feat(kubewarden-controller): Delete all CRs in pre-delete hook

On 1.36, without this change:
- Deleting a PolicyServer sets its policies as scheduled.
- Recommended policies are managed via Helm and removed when
  `kubewarden-defaults` is uninstalled.
- User-managed policies will never be deleted, and linger after
  the removal of the CRDs, as they have finalizers.

With this change:
All CRs will be removed when uninstalling the `kubewarden-controller`
chart. This includes charts of downstream consumers that use a single
chart approach.

The used image, kuberlr/kubectl, has busybox, hence `ash` as shell.
Use the shell to remove all CRs. Removing all CRs in potentially all
namespaces is costly; do backgrounds jobs with `&`, wait, and only
then remove the policyservers.

Signed-off-by: Víctor Cuadrado Juan <vcuadradojuan@suse.de>

Author: viccuad

charts/kubewarden-controller/templates/pre-delete-hook.yaml

@@ -36,7 +36,16 @@ spec:
       containers:
         - name: pre-delete-job
           image: '{{ template "system_default_registry" . }}{{ .Values.preDeleteJob.image.repository }}:{{ .Values.preDeleteJob.image.tag }}'
-          command: ["kubectl", "delete", "--all", "policyservers.policies.kubewarden.io"]
+          command:
+            - /bin/sh
+            - -c
+            - |
+              kubectl delete --wait --all clusteradmissionpolicies.policies.kubewarden.io &
+              kubectl delete --wait --all --all-namespaces admissionpolicies.policies.kubewarden.io &
+              kubectl delete --wait --all clusteradmissionpolicygroups.policies.kubewarden.io &
+              kubectl delete --wait --all --all-namespaces admissionpolicygroups.policies.kubewarden.io &
+              wait &&
+              kubectl delete --wait --all policyservers.policies.kubewarden.io
           env:
             - name: KUBERLR_ALLOWDOWNLOAD
               value: "1"