data quality: Complete site location fields to use additional Geo2 fields

[stephen-soltesz]

The set of fields used for site locations is limited to lat/lon, continent, country, city and states within the US (a subset of all sites). These values are down stream of information used by the original mlab-ns (location service). Now that M-Lab has standardized on Geo2 ISO3166-2 subdivisions, we can add additional fields to site locations to provide more complete Geo2 annotations.