Triggering ReservationStartedEvent / -EndedEvent without user interaction #354

- Added ReservationMade|DeletedEvents to iwsn-messages
- Added new methods getFutureReservations and getActiveAndFutureReservations to RSPersistence
- Updated event replay logic in ReservationManager to also replay ReservationMadeEvents for future reservations, thereby setting up the portals internal state correctly as if it were running uninterruptedly