Changes:
- Added Controller::removeServiceBooking() with proper documentation and
delegation to ServiceManagementService.
- Implemented ServiceManagementService::removeServiceBooking() to handle
cancellation of pending bookings, enforce status validation, send
notifications, and persist changes safely.
- Updated CustomerMenu to include a "Cancel Service Booking" option in
the menu, wired it into handleOperation, and implemented
CustomerMenu::cancelServiceBooking() for user interaction.
- Ensured consistent declarations in Controller.h,
ServiceManagementService.h, and CustomerMenu.h.
Fixes#2105
Jissin Mathew
b45463a66d