refactor: Sidenav to template

templates/decode.html

@@ -5,16 +5,7 @@
 
     {% include 'header.html' %}
 
-    <div class="navigation divv">
-        <div class="decore1"></div>
-        <nav class="navlink">
-                <a href="{{ url_for('index') }}" class="link">на главную</a>
-                <a href="{{ url_for('sql') }}" class="link">sql пипка</a>
-                <a href="{{ url_for('found') }}" class="link">forensic</a>
-                <!--    <a href="">rfi</a>-->
-                <!--    <a href="">lfi</a>-->
-        </nav>
-    </div>
+    {% include 'sidenav.html' %}
     <div id="popup-overlay">
         <div id="popup">