Fix License API model bean validation

The License object has incorrect bean validation rules set for fields:

@Min(1)
private long concurrentUserAppInstancesPerSeat;
@Min(1)
private long concurrentUserDevicesPerSeat;
@Min(1)
private long maxQtyPerUser;

The value 0 is reserved to mean that each of these rules may be in disabled mode. Equally, the correct @min value to use is 0.