Upgrade from Smarty 3 to Smarty 4 to be PHP 8.1 compatible

Remove all Smarty4 dedicated tests, all are done in the same test file
like before

www/lib/smarty-4.1.0/libs/plugins/modifiercompiler.indent.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * Smarty plugin
+ *
+ * @package    Smarty
+ * @subpackage PluginsModifierCompiler
+ */
+/**
+ * Smarty indent modifier plugin
+ * Type:     modifier
+ * Name:     indent
+ * Purpose:  indent lines of text
+ *
+ * @link   https://www.smarty.net/manual/en/language.modifier.indent.php indent (Smarty online manual)
+ * @author Uwe Tews
+ *
+ * @param array $params parameters
+ *
+ * @return string with compiled code
+ */
+function smarty_modifiercompiler_indent($params)
+{
+    if (!isset($params[ 1 ])) {
+        $params[ 1 ] = 4;
+    }
+    if (!isset($params[ 2 ])) {
+        $params[ 2 ] = "' '";
+    }
+    return 'preg_replace(\'!^!m\',str_repeat(' . $params[ 2 ] . ',' . $params[ 1 ] . '),' . $params[ 0 ] . ')';
+}