Add Former Countries for Birth Country selection

For simplicity, we are currently listing the current names of countries.
If we do this, we should do it consistently and change all the other countries too.

For example, the Russian Federation should be the Soviet Union for any babe born before '91. The same goes for all the countries that were part of the Soviet Union (Ukraine, Belarus, Estonia, Latvia, Lithuania, ...).

Another example: The Democratic Republic of the Congo should be split into 5 groups:
Before 1960: Belgian Congo
1960–1964: Republic of the Congo
1964–1971: Democratic Republic of the Congo
1971–1997: Zaire
1997–present: Democratic Republic of the Congo

Another difficult one is modern-day Kosovo.
Someone born in 1980: born in Yugoslavia
In 1995: born in Federal Republic of Yugoslavia
In 2007: born in Serbia
In 2015: born in Kosovo

It would be an enormous and confusing job. We don't think it's worth it, so we're rejecting this idea.

Thanks for bringing that up. We should fix that, for consistency.