Direct integration of Intel QSV H.264, H.265, VP9 and AV1 encoder

[Xaymar]

At the current time, StreamFX has no integration for QSV at all, which means that QSV users end up limited to the OBS Studio integrated QSV encoder. This leaves a bit of QSV's performance and quality on the table, as evidenced by the FFmpeg QSV integration being able to produce better quality than OBS Studio does.