Remove gitter

Author: mullermp

doc-src/templates/default/layout/html/footer.erb

@@ -4,7 +4,3 @@
   <%= YARD::VERSION %> (ruby-<%= RUBY_VERSION %>).
   <div id="awsdocs-legal-zone-copyright"></div>
 </div>
-
-<!-- Gitter chat -->
-<script>((window.gitter = {}).chat = {}).options = { room: 'aws/aws-sdk-ruby' };</script>
-<script src="https://sidecar.gitter.im/dist/sidecar.v1.js" async defer></script>