Use Gateway listener to reference routing peer (#150)

This just changes how a routing peer is referenced. In my head this
model makes more sense, especially as we need at least one listener
right now.

Signed-off-by: Philip Laine <philip.laine@gmail.com>

examples/gateway-api-public/gateway.yaml

@@ -13,14 +13,9 @@ metadata:
 spec:
   gatewayClassName: public
   listeners:
-  - protocol: HTTP
+  - protocol: gateway.netbird.io/NBRoutingPeer
+    name: netbird
     port: 80
-    name: dummy
-  infrastructure:
-    parametersRef:
-      group: netbird.io
-      kind: NBRoutingPeer
-      name: netbird
 ---
 apiVersion: netbird.io/v1
 kind: NBRoutingPeer