Add a QtAsyncio.run() function as the new recommended method to launch QtAsyncio programs. This abstracts the event loop policy and reduces the API to one single call. Additionally, this will allow to transparently replace the event loop policy with a loop factory when event loop policies are removed in Python 3.15 following their deprecation in 3.12. More information: https://discuss.python.org/t/removing-the-asyncio-policy-system-asyncio-set-event-loop-policy-in-python-3-15/37553 Pick-to: 6.6 Task-number: PYSIDE-769 Change-Id: I59d7eeb81debe92315351995f041caead4f51d8b Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io> Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>