Resize US to continental US

[Popolechien]

The current USA ZIM includes Hawaii and Alaska, but because of distances we end up with almost all of North America.

Much like we do not produce a ZIM file of France that extends all the way to Martinique or French Polynesia, we should break this down into three separate ZIM files, ie Continental Contiguous US, Hawaii and Alaska.

[Popolechien]

Flagging here because while it is possible to build a contiguous US map from the available .poly files, there does not seem to be independent Hawaii / Alaska files at the moment on geofabrik. They can build bespoke .poly files but there's an associated fee of 200-500€

[benoit74]

We should build our own poly file then. Not something extremely complex, but not very entertaining either ^^