Add mapping between countries to their iso languages

[moshewe]

There is no way to link a country to the language spoken in it using the library only as it's written right now. Solutions exist, E.g.: https://stackoverflow.com/questions/2680619/match-language-code-with-countries-where-this-language-is-an-official-or-commonl https://stackoverflow.com/questions/32773035/list-of-language-codes-iso639-1-in-python

Getting from a country to its languages will provide a consistent usage experience, just like with subdivisions and currencies.