KLocale: Add Country Subdivision Code setting

Add a setting to KLocale for the ISO 3166-2 Country level 2 code, i.e. country
divisions like States and Provinces.

For 4.6 this is simply a dumb repository for the value with no validation or
translation services provided. Code using the iso-codes project as a source
for validation and translation is being developed in kdepimlibs and kdebase
and will be moved into kdelibs in 4.7 once the api requirements and dependency
implications are better understood.