crd: added additionalPrinterColumns to GameServer

This outputs address, default port and status of each gameserver in
kubectl. This only works on Kubernetes >=1.11 and is ignored by older
versions.

```
$ kubectl get gameservers
NAME          STATE       ADDRESS        PORT
gds-example   Unhealthy   35.247.xx.xx   7777
```

install/helm/agones/templates/crds/gameserver.yaml

@@ -28,6 +28,16 @@ spec:
   group: stable.agones.dev
   version: v1alpha1
   scope: Namespaced
+  additionalPrinterColumns:
+  - JSONPath: .status.state
+    name: State
+    type: string
+  - JSONPath: .status.address
+    name: Address
+    type: string
+  - JSONPath: .status.ports[?(@.name=='default')].port
+    name: Port
+    type: string
   names:
     kind: GameServer
     plural: gameservers

install/yaml/install.yaml

@@ -446,6 +446,16 @@ spec:
   group: stable.agones.dev
   version: v1alpha1
   scope: Namespaced
+  additionalPrinterColumns:
+  - JSONPath: .status.state
+    name: State
+    type: string
+  - JSONPath: .status.address
+    name: Address
+    type: string
+  - JSONPath: .status.ports[?(@.name=='default')].port
+    name: Port
+    type: string
   names:
     kind: GameServer
     plural: gameservers