Real Traffic Density and Ratio ETS2 1.35.e

Changelog v1.35.e:
- reduced slow vehicles to minimum on normal roads
- increased slow on country roads
- reduced overall max_count for Ai vehicles (density not affected)

this update shall make better use of the slow vehicles, there should be seen very rarely now on the roads, and more on those country roads not open for traffic . the max_count reduction could help with keeping relatively low traffic count and therefore lower size in RAM. still density is not affected.