Fix preset saving
- Add an autotest to test preset saving and installation
To ensure this doesn't break again.
- faces: Split SensorFaceController::savePreset()
The method without arguments will still create and install the preset, but the actual preset creation now happens in a separate method that is passed the path to where data should be saved, so that we can more easily test whether that data is correct.
- faces: Ensure the temporary dir for a preset remains until installed
QTemporaryDir deletes the temporary directory when it goes out of scope. However, installing the preset with KPackage is an asynchronous operation that can extend beyond the current scope. This can cause the preset data to be deleted while we're still installing. To ensure this doesn't happen, extend the lifetime of the QTemporaryDir into the lambda we use to handle the job finished, so that it lives at least as long as the job.
- faces: Log an error if preset installation fails
Otherwise we just fail without any indication of what's happening
- faces: Fix identifier of logging category
This is not sensors