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/graphs/device/vpdn_tunnels_l2tp.inc.php

@@ -0,0 +1,21 @@
+<?php
+
+require 'includes/html/graphs/common.inc.php';
+
+$rrd_filename = rrd_name($device['hostname'], 'vpdn-l2tp');
+
+$stats = array('tunnels');
+
+$i = 0;
+foreach ($stats as $stat) {
+    $i++;
+    $rrd_list[$i]['filename'] = $rrd_filename;
+    $rrd_list[$i]['ds']       = $stat;
+}
+
+$colours = 'mixed';
+
+$nototal    = 1;
+$simple_rrd = 1;
+
+require 'includes/html/graphs/generic_multi_line.inc.php';