For get_countries_and_studies() API produce dict for each record
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
Merge branch 'ged-add-api-to-list-countries-and-subnational-regions' into exposure-export-UI-changes