[PRQ#76548] Merge Request for phonon-mpv

xiota [1] filed a request to merge phonon-mpv [2] into phonon-qt6-mpv [3]: Reorganized pkgbase. Converted from Qt5/Qt6 split package to Qt6-only package. Qt5 is EOL, and Qt5 version has zero pkgstats. [1] https://aur.archlinux.org/account/xiota/ [2] https://aur.archlinux.org/pkgbase/phonon-mpv/ [3] https://aur.archlinux.org/pkgbase/phonon-qt6-mpv/