Simplify layout and templates generation

app/Template/config/layout.php

@@ -1,10 +1,10 @@
 <section id="main">
     <section class="sidebar-container" id="config-section">
 
-        <?= $this->render('config/sidebar') ?>
+        <?= $this->render($sidebar_template) ?>
 
         <div class="sidebar-content">
-            <?= $config_content_for_layout ?>
+            <?= $content_for_sublayout ?>
         </div>
     </section>
 </section>

app/Template/config/sidebar.php

@@ -34,9 +34,6 @@
         <li <?= $this->app->checkMenuSelection('config', 'api') ?>>
             <?= $this->url->link(t('API'), 'config', 'api') ?>
         </li>
-        <li>
-            <?= $this->url->link(t('Documentation'), 'doc', 'show') ?>
-        </li>
         <?= $this->hook->render('template:config:sidebar') ?>
     </ul>
     <div class="sidebar-collapse"><a href="#" title="<?= t('Hide sidebar') ?>"><i class="fa fa-chevron-left"></i></a></div>