holidayregion.cpp - provide translatable strings for the German regions.

Summary:
The German holiday files now all have a proper country and name
since commits 4bdc6f618e77348eeafa5e802154b95febc27eab
and 8b3f65ed1f40975aa559881fc3116029b7e7677e

this patch allows those names to be translated.

also we can see the subdivision code in the regionName
in the case we have a subdivision but no name.
i.e say we have country "XX-YY" but name field is empty
then we have regionName = countyCode(XX)(yy)

Reviewers: vkrause

Reviewed By: vkrause

Subscribers: ltoscano, kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D29575