Add values and rendering for operating system of lines

[besentv]

Currently, many railroads in Germany are marked with the information of "No information available" for the used train protection. This is because most of these tracks are under a different operating system than driving with signals. To clarify this circumstance, it would be nice to have a tag for these rails where you can define the type of operating system used (e.g RIL-408 or RIL-436, RIL-437, same for other countries), so the map is more complete in the regard of no available information.

Cheers
Bernhard