feat: Initialize Symfony application structure with essential files

- Added index.php for application entry point.
- Created app.css for global styles.
- Introduced HomeController for handling the home route.
- Implemented Kernel class for application kernel.
- Added base.html.twig as the main template.
- Created index.html.twig for the home page layout.
- Set up Docker configurations for development and production environments.
- Included opcache configuration for development.

docker-compose.prod.yml

@@ -0,0 +1,6 @@
+services:
+  web:
+    environment:
+      APP_ENV: prod
+      APP_DEBUG: "0"
+      RESERVATION_DB_PATH: /data/reservations.sqlite