Find new source for OCONUS high-res spatial data

[lindsayplatt]

Currently have a target that downloads a spatial dataset from the National Weather Service because it was a shapefile and quick to incorporate. Would be better to use either USGS data (maybe from The National Map if that includes these islands) or from the Census Bureau's TIGER dataset.

Note that if you update the download target, you may need to also adjust:

1. Prepping the downloaded data into a readable shapefile, 2_process/out/nws_states.shp.
2. How the shapefile is used by the src/assets/anomaly_peaks.svg target: added as a depends and then hard-coded into the generate_single_oconus_sf() function.
3. The additional simplification steps applied to get rid of some strange straight lines by connecting points across the polygons that happens here within generate_single_oconus_sf()