Draft: [TESTING] temp/xdg-desktop-portal-phosh: fork from alpine, upgrade to 0.42.0_git20241214

Uses main branch of xdg-desktop-portal-phosh (and downloads pfs as subproject) to test out the new libadwaita file picker from https://gitlab.gnome.org/guidog/xdg-desktop-portal-phosh/-/merge_requests/8

To test: mrtest add 5906 and follow instructions in https://gitlab.gnome.org/guidog/xdg-desktop-portal-phosh/-/merge_requests/8