Add deepjavalibrary twitter to website (#542)

This adds an iframe embedding that includes the contents of the DJL twitter into
our site. Because that is where new DJL content is mostly added, it is the best
source for latest content and can be effortlessly put into making our site also
feature the latest DJL content.

Change-Id: I73c1779371619d94fc50575fc5e145e1d0342861

index.html

@@ -132,6 +132,12 @@ <h5 class="center">Ease of deployment</h5>
     </div>
 </div>
 
+<div class="container">
+    <div class="section">
+        <a class="twitter-timeline" data-height="800" data-dnt="true" href="https://twitter.com/deepjavalibrary?ref_src=twsrc%5Etfw">Tweets by deepjavalibrary</a> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
+    </div>
+</div>
+
 <div class="container">
     <div class="section">
         <h4 class="center">From our customers</h4>