♻️ move backups manifests in their owns folders

kubernetes/apps/default/cloudnative-pg/cluster/backups/kustomization.yaml

@@ -0,0 +1,13 @@
+---
+# yaml-language-server: $schema=https://json.schemastore.org/kustomization
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+namespace: default
+resources:
+  - ./external-backup.yaml
+configMapGenerator:
+  - name: postgres-external-backup
+    files:
+      - ./00-webhook
+generatorOptions:
+  disableNameSuffixHash: true