Add new font files, images, and initial index.php for CakePHP setup

- Added new font files: Cakedingbats (TTF, WOFF, WOFF2) and Raleway (various styles and encodings).
- Included new images: cake-logo.png, cake.icon.png, cake.logo.svg, and cake.power.gif.
- Created initial index.php file for handling requests in CakePHP framework.
- Added .gitkeep file in the js directory to maintain the folder structure.

templates/Error/error500.php

@@ -0,0 +1,16 @@
+<?php
+/**
+ * @var \App\View\AppView $this
+ * @var string $message
+ * @var string $url
+ */
+use Cake\Core\Configure;
+use Cake\Error\Debugger;
+
+// ...existing code...
+?>
+<h2>Wystąpił błąd wewnętrzny.</h2>
+<p class="error">
+    <strong>Błąd: </strong>
+    <?= h($message) ?>
+</p>