PoorEnvironmentTypeEnummixing up concepts

Poor environment conditions characterised by the PoorEnvironmentTypeEnum type.This allows you to indicate things like snow, heavy winds.dail, etc. Some of these conditions come along with reduced visibility. If you have an exact numerical value for visibility, you can code his using the minimumVisibilityDistance component. But very often you do not have such a numerical value, you just want to indicate that the conditions come alonf with reduced visibility.

How do you do that in DATEX II? You have "visibiliyReduced", nut that is also a literal in PoorEnvironmentTypeEnum! Hence, just to give one extra bit of boolean information (reduced visibility = yes), you have to create a Situation with two SituationRecords, with all the known caveats like duplicating location, etc. This is not acceptable!

Proposed Solution: Shift "visibilityReduced" (VIR) to a boolean attribute of the PoorEnvironmentCondition class.