Reservation-Scheduler should show reservations in UTC

[pschuler78]

AircraftReservations have UTC time and the scheduler shows local time. This will result in a non expected view of reservations. E.g. an all day reservation for 20.1.2018 will be shown from 1am on 20.1.2018 until 1am on 21.1.2018, which is a bit confusing.