Add FIPS code to counties from NYT source

[lxu213]

Currently, the counties from the NYT source are assigned IDs that don't abide to any standard. If they were assigned an FIPS county code which are used by the US Census Bureau to uniquely identify geographic features, it would be much easier to join, identify, and parse.

I'm not sure the best approach to implementing this while maintaining backwards compatibility. However if this is something others are also interested in and we can come up with a suitable strategy, I would be happy to open a PR for this if the team has the capacity to review it.

[Kilo59]

This sounds like a good idea.

I've been meaning to start a discussion thread about potentially a v3 of the API, we wouldn't need to worry about backward compatibility in that case.
I think being able to access the nested locations with sensible ids would be part of that.
GET v3/countries/<country_code> or just v3/<country_code>
GET v3/countries/<country_code>/<state/province>
GET v3/countries/<country_code>/<state/province>/<county_code/county_name>

Example

GET v3/us/texas/48015 or GET v3/us/texas/austin
Or even
GET v3/countries/us/states/texas/counties/austin

[lxu213]

@Kilo59 that's great a v3 of the API will be discussed soon! Being able to access either using FIPS county code or by using county name would be great.