Reservations: When a reservation is used, send reservation update.

[maaikez]

Describe the problem

When a reservation is used, we can send a ReservationUpdateStatus to let other parts of the system know about it. We need an extra callback for this.

EVerest Domain

Other

Affected EVerest Module

everest core

Describe your solution

After calling
this->reservation_handler.on_reservation_used(reservation_id.value());
in the AuthHandler, we should call a function to send a ReservationUpdateStatus.

Additional context

No response