templates/layout: Remove no longer used topbar

It got displayed again after reintegration of custom CSS rules but
it should have been removed since a while.

docs/_static/custom.css

-a {
-    border-bottom-style: none;
-    outline: none;
-    text-decoration: none;
-}
-
-.swh-top-bar {
-    direction: ltr;
-    height: 30px;
-    position: fixed;
-    top: 0;
-    left: 0;
-    width: 100%;
-    z-index: 99999;
-    background-color: #262626;
-    color: #fff;
-    text-align: center;
-    font-size: 14px;
-}
-
-.swh-top-bar ul {
-    margin: 0;
-    margin-top: 6px;
-    white-space: nowrap;
-}
-
-.swh-top-bar li {
-    display: inline-block;
-    margin-left: 10px;
-    margin-right: 10px;
-}
-
-.swh-top-bar a,
-.swh-top-bar a:visited {
-    color: white;
-}
-
-.swh-top-bar a.swh-current-site,
-.swh-top-bar a.swh-current-site:visited {
-    color: #fecd1b;
-}
-
-.swh-donate-item {
-    position: absolute;
-    right: 0;
-}
-
-.swh-donate-link {
-    border: 1px solid #fecd1b;
-    background-color: #e20026;
-    color: white !important;
-    border-radius: 3px;
-    margin-top: -2px;
-    padding-top: 3px;
-    padding-left: 3px;
-    padding-right: 3px;
-    padding-bottom: 3px;
-}
-
-/* Prevent overlaps with top bar and anchors */
-:target::before {
-    content: "";
-    display: block;
-    height: 30px;
-    margin: -30px 0 0;
-}
-
 /* Alegreya font setup */
 
 /* alegreya-400normal - latin */

docs/_templates/layout.html

@@ -36,26 +36,3 @@
       <li class="toctree-l1"><a href="/sysadm/">System Administration</a></li>
   </ul>
 {%- endblock %}
-
-{% block content %}
-  <div class="swh-top-bar">
-    <ul>
-      <li>
-        <a href="https://www.softwareheritage.org">Home</a>
-      </li>
-      <li>
-        <a href="https://archive.softwareheritage.org">Archive</a>
-      </li>
-      <li>
-        <a href="https://forge.softwareheritage.org/">Development</a>
-      </li>
-      <li>
-        <a class="swh-current-site" href="https://docs.softwareheritage.org/devel/">Documentation</a>
-      </li>
-      <li class="swh-donate-item">
-        <a class="swh-donate-link" href="https://www.softwareheritage.org/donate/">Donate</a>
-      </li>
-    </ul>
-  </div>
-  {{ super() }}
-{% endblock %}