ki18n: export Kuit::setupForDomain, unittest KUitSetup::setFormatForMarker

Summary:
This was initially to test the port to QRegularExpression in D26366,
it turned out that setupForDomain was meant to be exported, since
KUitSetup was exported.

Test Plan: test passes

Reviewers: ilic

Reviewed By: ilic

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D26408