feat(env): add GTAG_MEASUREMENT_ID to env and config

- Added GTAG_MEASUREMENT_ID to .env.example
- Updated 'GTAG_MEASUREMENT_ID' in config/app.php
- Modified script tag in googletag.blade.php to use dynamic ID

resources/views/components/googletag.blade.php

@@ -1,8 +1,8 @@
-<script async src="https://www.googletagmanager.com/gtag/js?id=G-RF1MDHRWS0"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id={{ config('app.GTAG_MEASUREMENT_ID') }}"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'G-RF1MDHRWS0');
+  gtag('config', '{{ config('app.GTAG_MEASUREMENT_ID') }}');
 </script>