Validating constructor arguments for BootChargingStationCommand
Removed unnecessary defensive copy in BootChargingStationCommand
Documented BootChargingStationCommand
Simplified ChargingStationBootedEvent

- ChargingStationBootedEvent is no longer abstract.
- Registered and unregistered variants of the above event are deleted.
- Removed logic which applies these events.
Simplified BootChargingStationCommand handler
Using primitives for attributes of ChargingStation

Using primitives to prevent NullPointerExceptions.
Validating constructor arguments for ChargingStationBootedEvent