Contains the map and other data that drives SLP for each country.
ccTLD is the region parameter for Google Maps
ccTLD is any of the Unicode region subtag identifiers
See https://developers.google.com/maps/coverage for a list of supported regions, 2D/3D map tiles apply here
\SLP_Country_Manager::load_country_data sets up the list of country meta data for this purpose.
It has not been updated since 2018.