Integrate meta-seconorth-distro/fix_qt_tests

Commit: seco-ne/yocto/layers/meta-seconorth-distro@a35910ae

packages:tests: Moved Qt tests to packagegroup-seconorth-qt

The Qt tests in the general tests packagegroup trigger a full Qt build (even for images and distros that don't include Qt). This leads to unnecessary long build times. Moved the tests to the Qt packagegroup, to ship around this issue.