Dev-Umgebung: Kompatibilität für PHP 8.3 + Smarty 4.5.6

- Smarty 4.1.1 → 4.5.6 (behebt dynamic property deprecations)
- Core-Klassen: #[\AllowDynamicProperties] für Admin_role, base, Config,
  Customer, Customer_group, CustomerGroups, Item, Structure, website
- website.class.php: counts[parent_id] initialisieren vor ++ (PHP 8.1)
- layout.class.php: HTTP_ACCEPT_LANGUAGE mit isset-Guard
- website_init.php: session_status()-Check vor session_start
- .htaccess: HTTPS-Redirect via X-Forwarded-Proto (statt SERVER_PORT)
- themes/easyshop_advanced/media/: Parent-Theme-Assets nachgezogen
- .gitignore: smarty.4.1.1.bak ausschließen

libs/smarty/docs/programmers/api-functions/api-set-plugins-dir.md

@@ -0,0 +1,46 @@
+setPluginsDir()
+
+set the directories where plugins are stored
+
+Description
+===========
+
+Smarty
+
+setPluginsDir
+
+string\|array
+
+plugins\_dir
+
+
+    <?php
+
+    // set a single directory where the plugins are stored
+    $smarty->setPluginsDir('./plugins');
+
+    // view the plugins dir chain
+    var_dump($smarty->getPluginsDir());
+
+    // set multiple directoríes where plugins are stored
+    $smarty->setPluginsDir(array(
+        './plugins',
+        './plugins_2',
+    ));
+
+    // view the plugins dir chain
+    var_dump($smarty->getPluginsDir());
+
+    // chaining of method calls
+    $smarty->setTemplateDir('./templates')
+           ->setPluginsDir('./plugins')
+           ->setCompileDir('./templates_c')
+           ->setCacheDir('./cache');
+
+    ?>
+
+       
+
+See also [`getPluginsDir()`](#api.get.plugins.dir),
+[`addPluginsDir()`](#api.add.plugins.dir) and
+[`$plugins_dir`](#variable.plugins.dir).