[DOCS] Zeppelin Flink Spark tutorial

Moon recommended I migrate a How To tutorial I wrote into the website.

http://mail-archives.apache.org/mod_mbox/incubator-zeppelin-users/201511.mbox/browser

I didn't create a JIRA issue, it doesn't look like that is nessicary for website updates? If it is, I'm sorry I'll go make one. Sorry, I'm new.

Author: rawkintrevo <trevor.d.grant@gmail.com>

Closes #418 from rawkintrevo/zeppelin-flink-spark-tutorial and squashes the following commits:

0cd86b3 [rawkintrevo] [DOCS] Flink and Spark Cluster Tutorial

docs/_includes/themes/zeppelin/_navigation.html

@@ -33,6 +33,7 @@
                 <li role="separator" class="divider"></li>
                 <li class="title"><span><b>More</b><span></li>
                 <li><a href="{{BASE_PATH}}/install/upgrade.html">Upgrade Zeppelin Version</a></li>
+                <li><a href="{{BASE_PATH}}/quickstart/install_with_flink_and_spark_cluster.html">Install Zeppelin with Flink and Spark Clusters Tutorial</a></li>
               </ul>
             </li>
             <li>