fix: cattle-system namespace (#399)

- cattle-system namespace is created earlier than helm
- leave namespaces.yaml to manage cattle-system namespace (required
  before installing helm/rancher)

Reviewed-on: #399

modules/rke2/files/ingress-route-rancher.yaml

@@ -0,0 +1,22 @@
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: rancher
+  namespace: cattle-system
+  annotations:
+    kubernetes.io/ingress.class: nginx
+spec:
+  tls:
+    - hosts: [rancher.main.unkin.net]
+      secretName: tls-rancher
+  rules:
+    - host: rancher.main.unkin.net
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: rancher
+                port:
+                  number: 80