bitcoin-paper: Add Greek Translation

_templates/bitcoin-paper.html

@@ -36,7 +36,16 @@ id: bitcoin-paper
             <span>{% translate translated_by %}</span>
             <a href="https://github.com/99coins">99coins</a>
           </div>
-        </li>     
+        </li>  
+
+        <li class="card bitcoin-paper-card">
+          <img src="/img/flags/gr.png?{{site.time | date: '%s'}}" alt="Greek flag">
+          <a class="language-link" href="/files/bitcoin-paper/bitcoin_gr.pdf">Italiano</a>
+          <div>
+            <span>{% translate translated_by %}</span>
+            <a href="https://github.com/chdimosthenis">chdimosthenis</a>
+          </div>
+        </li>   
 
         <li class="card bitcoin-paper-card">
           <img src="/img/icons/flag_spanish.svg?{{site.time | date: '%s'}}" alt="Spanish flag">