add gateway and http route

clusters/k3s-dgx/infrastructure/gateway.yaml

@@ -0,0 +1,12 @@
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  name: envoy-gateway
+  namespace: default
+spec:
+  gatewayClassName: envoy
+  listeners:
+    - name: http
+      protocol: HTTP
+      port: 80
+      hostname: "llm.mycompany.com"