Add 2 API methods for (1) getting the list of countries in GED and (2) getting the geographic regions by ISO
Merge branch 'ged-add-api-to-list-countries-and-subnational-regions' of https://github.com/gem/oq-platform into ged-add-api-to-list-countries-and-subnational-regions
two part menu for getting country and sub national regions