### TL;DR
Reorganized booking service code and removed unused BookingRequest model
### What changed?
- Moved Payment model from payment.go to models.go
- Relocated payment-related service methods from service.go to payment.go
- Removed unused BookingRequest struct
- Updated dependencies to their latest versions
### How to test?
1. Run database migrations to verify removal of BookingRequest model
2. Test all payment-related endpoints to ensure functionality remains intact:
- GET /payments/{id}
- POST /payments
- PUT /payments/{id}
### Why make this change?
- Improves code organization by grouping payment-related code together
- Removes unused BookingRequest model to reduce technical debt
- Keeps dependencies up to date for security and performance improvements
