QtQuick Test test suites directly from PySide2

Users have requested possibility to do QtQuick Test test suites directly from PySide2.

User use case:

"

We would like to run some end-to-end tests on the entire application, starting from the QML front-end. However, the Qt pages on Qt Quick Test (https://doc.qt.io/qt-5/qtquicktest-index.html) suggest that we should set up a C++ test harness to do this. We would prefer to avoid this given that we would like to avoid having to set up a C++ development tool chain just to run these tests.

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