Enable scripted effects to load config translations from the kpackage
By default translations are loaded from /usr/share/locale. This works fine for builtin effects since we install our translations there.
However, it doesn't work for third-party scripted effects. They only provide a kpackage and can't install anything to /usr/share/.
This patch allows them to ship translations in contents/locale/language/LC_MESSAGES/
domain.mo,
where $domain is the X-KWin-Config-TranslationDomain metadata value
This matches what Plasma does for applets since https://phabricator.kde.org/D5209