bitcoin-paper: add braille version

Author: RandyMcMillan

_templates/bitcoin-paper.html

@@ -357,6 +357,15 @@ <h1>{% translate pagetitle %}</h1>
          </div>
         </li>
 
+        <li class="card bitcoin-paper-card">
+         <a class="language-link"
+           href="/files/bitcoin-paper/bitcoin-braille.pdf">Braille</a>
+         <div>
+           <span>{% translate translated_by %}</span>
+           <a href="https://github.com/neatnik/braille-bitcoin-whitepaper">@NeatNik</a>
+         </div>
+        </li>
+
       </ul>
 
       <p>{% translate submit_new_translation %}</p>