title: How to find the installed plugin on elasticsearch?
body: <p>Is there way to find the installed plugin on elasticsearch? 
  Currently there are few plugins installed but I don't know what are those plugin and how to access them. I know few of them, but I want a list of all plugin which are installed.</p>
  
  <p>e.g few plugin url:</p>
  
  <pre><code>http:://&lt;HOSTNAME&gt;:9200/_plugin/bigdesk/#nodes
  http:://&lt;HOSTNAME&gt;::9200/_plugin/kopf/#!/nodes
  </code></pre>