Add low-zoom road toll property from Natural Earth

The toll information added for https://github.com/tilezen/vector-datasource/issues/1553 is only there for OSM zooms, but Natural Earth also has a toll property. Let's add that for low zooms via this issue.

_Originally posted by @nvkelso in https://github.com/tilezen/vector-datasource/issues/1553#issuecomment-460146384_