icar MilkCharateristicCodeType enum - create md file in the well-known section and link this

[erwinspeybroeck]

[erwinspeybroeck]

Tomas wants to get the milk characteristic codes more discoverable and explained. He will create a ;MD file in the well-known section. In the icar MilkCharateristicCodeType enum he will put the link to that md file in the description.