Add timezones for countries

[ajmaln]

Use case for the feature

Will be helpful in identifying timezones based on countries and vice versa

Examples or links

https://en.wikipedia.org/wiki/List_of_time_zones_by_country

[dmythro]

I think it makes sense. Need to check the nice way to add this data, and probably the minimal data to import so the rest can be handled by a separate library (like TZ names/variants etc).

I'd probably also add capital coordinates as well.

[firmianaQ]

like this countries-and-timezones