Setup sandbox for GCP proxy

1) Clean up alpha config to only allow alpha proxy, removing test proxy client id.
2) Add sandbox service account client id to sandbox config.
3) Add sandbox config to nomulus and proxy, remove TEST environment, which is not being used anymore. (Test now uses LOCAL.)
4) Add sandbox kubenetes config

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=193400909

java/google/registry/proxy/kubernetes/proxy-deployment-sandbox.yaml

@@ -0,0 +1,65 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  namespace: default
+  name: proxy-deployment
+  labels:
+    app: proxy
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: proxy
+  template:
+    metadata:
+      labels:
+        app: proxy
+    spec:
+      containers:
+      - name: proxy
+        image: gcr.io/GCP_PROJECT/IMAGE_NAME:bazel
+        ports:
+        - containerPort: 30000
+          name: health-check
+        - containerPort: 30001
+          name: whois
+        - containerPort: 30002
+          name: epp
+        readinessProbe:
+          tcpSocket:
+            port: health-check
+          initialDelaySeconds: 5
+          periodSeconds: 10
+        livenessProbe:
+          tcpSocket:
+            port: health-check
+          initialDelaySeconds: 15
+          periodSeconds: 20
+        imagePullPolicy: Always
+        args: ["--env", "sandbox"]
+        env:
+        - name: POD_ID
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.name
+        - name: NAMESPACE_ID
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.namespace
+        - name: CONTAINER_NAME
+          value: proxy
+---
+apiVersion: autoscaling/v2beta1
+kind: HorizontalPodAutoscaler
+metadata:
+  namespace: default
+  name: proxy-autoscale
+  labels:
+    app: proxy
+spec:
+  scaleTargetRef:
+    apiVersion: extensions/v1beta1
+    kind: Deployment
+    name: proxy-deployment
+  maxReplicas: 5
+  minReplicas: 1