Update country code names to match database

[peppy]

Required for ASS / osu-web cross-compatibility

[nanaya]

I haven't checked the rest but at least CZ doesn't match either

[peppy]

Yeah I figure there are others. Wasn't really bothering since these are the only in world cups so far, but I'll do a full pass i guess.

[bdach]

Not sure what to think of this change because apparently neither source is really consistent with each other, or current reality. The updated list of countries:

• contains countries that don't exist anymore ("Netherlands Antilles"),
• doesn't contain countries that exist now ("South Sudan" - see the compile failure caused by that even),
• has entries like "Anonymous Proxy", "Satellite Provider", or "Other"

But I guess as long as the ground truth is matching then it's probably fine. Just need to fix the compile failure somehow (by either re-adding the missing enum member or deleting the mapping from CountryExtensions).

Oh and any of the countries added here will throw if the "Add all countries" button is used in the tournament client:

osu/osu.Game.Tournament/CountryExtensions.cs

Lines 765 to 766 in 05d7516

	default:
	throw new ArgumentOutOfRangeException(nameof(country));