add linkedin link at the bottom

_includes/footer.html

@@ -12,6 +12,7 @@
         <ul>
           <li><a href="https://github.com/simbricks" class="github" title="GitHub"></a></li>
           <li><a href="https://twitter.com/sim_bricks" class="twitter" title="Twitter"></a></li>
+          <li><a href="https://www.linkedin.com/company/simbricks/" class="linkedin" title="LinkedIn"></a></li>
           <li><a href="https://join.slack.com/t/simbricks/shared_invite/zt-16y96155y-xspnVcm18EUkbUHDcSVonA" class="slack" title="Slack"></a></li>
         </ul>
       </nav>

_sass/base-design.scss

@@ -231,6 +231,9 @@ footer {
       a.twitter::before {
         content: "\f099";
       }
+      a.linkedin::before {
+        content: "\f08c";
+      }
     }
   }
 }

_sass/base-layout.scss

@@ -142,11 +142,14 @@ footer {
       justify-content: center;
       flex-wrap: wrap;
       div.mpisws-logo, nav, div.tumvl-logo {
-        width: 15rem;
+        width: 13rem;
         img {
           margin: 1rem;
         }
       }
+      nav {
+        width: 17rem;
+      }
       div.mpisws-logo {
         img {
           width: 5rem;