bitcoin-paper: Add Vietnamese Translation

_templates/bitcoin-paper.html

@@ -127,6 +127,15 @@ id: bitcoin-paper
             <a href="https://github.com/hanspandeya">hanspandeya</a>
           </div>
         </li>
+
+        <li class="card bitcoin-paper-card">
+          <img src="/img/icons/flag_vi.svg?{{site.time | date: '%s'}}" alt="Vietnamese flag">
+          <a class="language-link" href="/files/bitcoin-paper/bitcoin_vi.pdf">Tiếng Việt</a> 
+          <div>
+            <span>{% translate translated_by %}</span>
+            <a href="https://github.com/pcdinh">Pham Cong Dinh</a>
+          </div>
+        </li>
       </ul>
   
       <p>{% translate submit_new_translation %}</p>