Model point of view for disputed lines that should render from OSM

[nvkelso]

Following up from 2nd round of work in #1810.

• What did you see? Some countries like Pakistan have opinions about their shared border with another country. We model that correctly. But we don't currently allow OSM model ETL for recognizing other disputed boundaries outside of that country, eg between India and China.
• What did you expect to see? For the Pakistan POV, some of the India & China frontier boundary lines should disputed instead of just country. We do this correctly at mid-zooms from Natural Earth, but not at high zooms from OSM.
• What map location are you having problems with? City and country are helpful, as well as tile coordinates or latitude / longitude.
• Screenshot? Props for animated gifs.

NE low zoom:

NE mid-zoom:

OSM high-zoom (red lines shown as white in error)

[nvkelso]

This is done now