feat: Let flux manage cilium after bootstrap

controllers/cilium/cilium.yaml

@@ -0,0 +1,15 @@
+apiVersion: kustomize.toolkit.fluxcd.io/v1
+kind: Kustomization
+metadata:
+  name: cilium
+  namespace: flux-system
+spec:
+  interval: 1h
+  retryInterval: 2m
+  timeout: 5m
+  sourceRef:
+    kind: ExternalArtifact
+    name: cilium
+  path: ./${cluster_env}
+  prune: true
+  wait: true