Refine `country_code` definitions in all locales to ensure only relevant data is included

[ejcheng]

trafficstars

Our country_code definitions are inconsistent at this time. We should consider going through each locale's country_code definitions and ensure that the only entries in that locale are countries that are relevant (proximity, etc) to the selected locale. Also, we would need to refine our JSDocs to explain this.

This issue is an expanded form of #1861.

• de_CH #2304
• fr_CH- doesn't look like any changes are needed

[xDivisionByZerox]

Team decision:

We generally want this. More generic locales (en, de) should contain a wider range of relevant contry codes. The more specific a locale gets, the more specific the country codes should be as well.

All locale groups changes should be provided in a separate PR to allow for more fine grained research on those locales.