Use kustomize and envsubst to generalize k8s config.

Adds a [kustomize](https://github.com/kubernetes-sigs/kustomize) overlay
for a new staging environment. Additionally, adds environment variables
in the place of certain pieces of information that need to be templated.

The K8s README ("deploy/README.md") has been updated to reflect the new
method for applying config.

This commit also removes the configuration for the AWS cluster and
references to AWS in the README.

deploy/overlays/staging/json_ports.yml

@@ -0,0 +1,12 @@
+- op: replace
+  path: /spec/template/spec/containers/1/ports/0/containerPort
+  value: 9342
+- op: replace
+  path: /spec/template/spec/containers/1/ports/1/containerPort
+  value: 9442
+- op: replace
+  path: /spec/template/spec/containers/1/ports/2/containerPort
+  value: 9343
+- op: replace
+  path: /spec/template/spec/containers/1/ports/3/containerPort
+  value: 9443

deploy/overlays/staging/kustomization.yaml

@@ -0,0 +1,15 @@
+namespace: staging
+bases:
+  - ../../azure/
+resources:
+  - namespace.yml
+patchesStrategicMerge:
+  - replica_count.yml
+  - ports.yml
+patchesJson6902:
+  - target:
+      group: extensions
+      version: v1beta1
+      kind: Deployment
+      name: atst
+    path: json_ports.yml

deploy/overlays/staging/namespace.yml

@@ -0,0 +1,4 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: staging

deploy/overlays/staging/ports.yml

@@ -0,0 +1,28 @@
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: atst-main
+spec:
+  loadBalancerIP: 40.76.217.62
+  ports:
+  - port: 80
+    targetPort: 9342
+    name: http
+  - port: 443
+    targetPort: 9442
+    name: https
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: atst-auth
+spec:
+  loadBalancerIP: 40.87.14.233
+  ports:
+  - port: 80
+    targetPort: 9343
+    name: http
+  - port: 443
+    targetPort: 9443
+    name: https

deploy/overlays/staging/replica_count.yml

@@ -0,0 +1,14 @@
+---
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: atst
+spec:
+  replicas: 2
+---
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: atst-worker
+spec:
+  replicas: 1