feat!: Separate out internal and external nginx controllers (#880)

bootstrap/templates/kubernetes/apps/flux-system/addons/webhooks/github/ingress.yaml.j2

@@ -5,10 +5,10 @@ metadata:
   name: flux-webhook
   namespace: flux-system
   annotations:
-    external-dns.alpha.kubernetes.io/target: "ingress.${SECRET_DOMAIN}"
+    external-dns.alpha.kubernetes.io/target: "external.${SECRET_DOMAIN}"
     hajimari.io/enable: "false"
 spec:
-  ingressClassName: nginx
+  ingressClassName: external
   rules:
     - host: &host "flux-webhook.${SECRET_DOMAIN}"
       http: