Support province name translation

Currently, the location module use language independent provinces names. For instance, the name for the Belgian province with code WBR will always be ""Brabant Wallon", regardless of the language set for the site or by the user. But this is its French name and it has a different name in English ("Walloon Brabant") and in Dutch ("Waals-Brabant").

A solution may be to cache province names by language in location_get_provinces and to return translated names in location_province_list_$country (see attached patch).