Delete twitter link

Hinted by @maipet here: https://metadaten.community/t/twitter-logo-bei-mf-docu/661

Author: TobiasNx

navigation.html

@@ -17,8 +17,6 @@
           
         </br>
         <a href='https://openbiblio.social/@metafacture'><img src='./img/Mastodon.png'/></a>
-
-        <a href='https://twitter.com/metafacture'><img src='./img/Twitter.png'/></a>
         <a href='https://github.com/metafacture'><img src='./img/GitHub.png'/></a>
     </b>
 </center>