Remove unit and rules from osi3::LidarDetection::intensity

[ClemensLinnhoff]

Describe the feature

Currently, the field osi3::LidarDetection::intensity has the unit % and per the defined rules can have values between 0 and 100 (which makes sense for %). However, real lidar sensors have a variety of different intensity definitions.

I my opinion, the intensity output of a sensor model should be in the same unit and scale as in the corresponding real sensor.
Therefore, I propose to remove the unit specification and the value rules.

Describe alternatives you have considered

The alternative now is to scale the intensity in the subsequent logical model. However, intensity scaling should be part of the sensor model and not a logical model.

Describe the backwards compatibility

The intensity value is already a double. So there should be no issue. Only the documentation would be changed.