Security fix: unauthorized access (#10091)

* Security fix: unauthorized access
Affects nginx users:
Moved php files outside of public html directory (Apache was protected by .htaccess)

Affects all users:
Some files did not check for authentication and could disclose some info.
Better checks before including files from user input

* git mv html/includes/ includes/html
git mv html/pages/ includes/html/

includes/html/pages/graylog.inc.php

@@ -0,0 +1,28 @@
+<?php
+/*
+ * LibreNMS
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.  Please see LICENSE.txt at the top level of
+ * the source code distribution for details.
+ *
+ * @package    LibreNMS
+ * @subpackage webui
+ * @link       http://librenms.org
+ * @copyright  2017 LibreNMS
+ * @author     LibreNMS Contributors
+*/
+$no_refresh = true;
+$pagetitle[] = 'Graylog';
+
+echo '<div class="panel panel-default panel-condensed">
+    <div class="panel-heading">
+        <strong>Graylog entries</strong>
+    </div>';
+
+require_once 'includes/html/common/graylog.inc.php';
+echo implode('', $common_output);
+
+echo '</div>';