Add the ability to search a country by `ISO 3166-1 alpha-3` codes (e.g. USA, JPN, CHE)

[rakleed]

Issue Details

You've added ISO 3166-1 alpha-2 country searches, but I would like to be able to use 3-letter abbreviations as well.

Proposed solution

Add a country search using ISO 3166-1 alpha-3 codes (e.g. USA, JPN, CHE).

Also, please make the country search for ISO 3166-1 codes case-insensitive (e.g. so I can find the United States with Us and us queries).

Alternative solution

No response

[maxikuzmin]

@rakleed thanks! We'll add country codes in the next updates