Add Creative Elements templates and update index files

- Introduced new templates for catalog, checkout, contact, and error pages.
- Implemented caching headers and redirection in index.php files across various directories.
- Enhanced product and layout templates for better integration with Creative Elements.
- Added backoffice header styles and scripts for improved UI/UX in the admin panel.

modules/creativeelements/views/js/editor-preview.js

@@ -0,0 +1,8 @@
+/*!
+ * Creative Elements - live Theme & Page Builder
+ * Copyright 2019-2022 WebshopWorks.com
+ */
+if (!$('#elementor').length && location.search.indexOf('&force=1&') < 0) {
+	// redirect to preview page when content area doesn't exist
+	location.href = cePreview + '&force=1&ver=' + Date.now();
+}