Add option "read_and_close", improve page loading (only for PHP > 7.0)

main/inc/lib/chamilo_session.class.php

@@ -92,7 +92,9 @@ class ChamiloSession extends System\Session
         ini_set('session.use_trans_sid', 0);
 
         session_name(self::NAME);
-        session_start();
+        // read_and_close option improve page load speed see:
+        // http://php.net/manual/en/migration70.new-features.php#migration70.new-features.session-options
+        session_start([ 'read_and_close' => true]);
         $session = self::instance();
         if ($already_installed) {
             if (!isset($session['checkChamiloURL'])) {