feat(webhook): Implement Xendit Snap Webhook handling
Created by: alfianhs
- Added middleware for Xendit authentication.
- Created new webhook route handler for Xendit.
- Implemented XenditSnapWebhook function to process incoming webhook requests.
- Updated purchase model to include new fields for handling ticket purchases.
- Created ticket purchase repository with CRUD operations.
- Added new use case for handling Xendit webhooks.
- Updated email helpers to send attachments.
- Enhanced purchase creation logic to accommodate new ticket purchase structure.
- Updated Swagger documentation to include new webhook endpoint and request definitions.
- Added QR code generation functionality for ticket purchases.