feat: Add Discord alert webhook, ContactCategory enum, form request

- Added Discord alert webhook URL to .env.example
- Created ContactCategory enum with humanReadable method
- Implemented ContactSubmissionRequest form request
- Added ContactSubmission model with fillable and casts properties
- Included configurations for Discord alerts and honeypot protection

composer.json

@@ -26,6 +26,8 @@
         "saade/blade-iconsax": "^1.1",
         "simonhamp/the-og": "^0.5.4",
         "spatie/laravel-backup": "^8.3",
+        "spatie/laravel-discord-alerts": "^1.3",
+        "spatie/laravel-honeypot": "^4.4",
         "spatie/laravel-query-builder": "^5.6",
         "spatie/sheets": "^1.10",
         "sqids/sqids": "^0.4.1"