[simple] link preferences on /about and /stats

We want to link the preferences from every page
(except of course the preferences page).

searx/templates/simple/index.html

@@ -4,7 +4,6 @@
 	<link rel="preload" href="{{ url_for('static', filename='img/searxng.png') }}" as="image" />
 {% endblock %}
 {% block content %}
-<nav id="linkto_preferences"><a href="{{ url_for('preferences') }}">{{ icon_big('menu-outline') }}</a></nav>
 <div class="index">
     <div class="title"><h1>SearXNG</h1></div>
     {% include 'simple/simple_search.html' %}