Remove Slack link on main page

It doesn't really allow people to find/discover/request access to it
anyways. I think having a dedicated web-form for events would make
sense, but otherwise people should have to request access I think?

Author: Hippocrates

templates/default.html

@@ -49,15 +49,14 @@
             <li><a href="/conduct">Code of Conduct</a></li>
             <li><a href="/organizers">Organizers</a></li>
             <li><a href="/contact">Contact</a></li>
-            <li><a href="/in-memoriam-michael">In Memoriam: Michael</a></li>
           </ul>
           <ul>
             <li><a href="/meetup">Meetup</a></li>
             <li><a href="/luma">Luma</a></li>
             <li><a href="/buttondown">Buttondown</a></li>
-            <li><a href="/slack">Slack</a></li>
             <li><a href="/github">GitHub</a></li>
             <li><a href="/mastodon">Mastodon</a></li>
+            <li><a href="/in-memoriam-michael">In Memoriam: Michael</a></li>
           </ul>
         </nav>
       </header>