Add import script for fixing route types and display names in NL

[vkrause]

There's still some room for improvement on regional services, but that requires a bit more research first.

[jbruechert]

Are the values taken from NS / physical departure boards?

[vkrause]

The local departure boards actually only seem to show what's currently in the route name ("Intercity", "Sprinter", etc, without a number). That's not ideal for the cross-border routes though, we should IMHO have the same name for those everywhere.

The current implementation does this for long-distance services, but there's also local cross-border services. Those seem to be labeled as "Sneltrein [RE|RB]NN" for e.g. DB services (unlike the domestic ones which are just "Sneltrein"), and IMHO also should be renamed for consistency. I yet have to figure out whether that actually holds for all of them though.