Provide a %_releasecountries% variable

The existing "releasecountry" tag contains a single release country as returned in the country field for a release as returned by the MB web service. If there are multiple release countries only the first is used (in alphabetical order it seems).

Picard should provide a %_releasecountries% variable with the complete list of all countries. That way the user can choose scripting to choose to display either a different country or even assign the list to the %releasecountry% tag