Updating Spark Example.

Few usability improvements:

- Added a proxy to enable viewing worker logs
- Removed seperate webui service
- Modified Zeppelin and spark-ui services to be Loadbalancers
- Changed pyspark example to be platform agnostic
- Improved kubectl context setup
- Minor grammar/flow fixes

examples/spark/spark-ui-proxy-service.yaml

@@ -0,0 +1,12 @@
+kind: Service
+apiVersion: v1
+metadata:
+  name: spark-ui-proxy
+  namespace: spark-cluster
+spec:
+  ports:
+    - port: 80
+      targetPort: 80
+  selector:
+    component: spark-ui-proxy
+  type: LoadBalancer