* (Qt) Migrate to Qt6
* basic support Qt6 with minimal changes required for compiling
* look `moc` in QT_HOST_LIBEXECS
* (Qt) Backward compatibility with Qt5
- Startup Summary split off from Verbose Mode, added option to hide for games with zero core cheevos
- Some existing options moved into this submenu
- Leaderboard-related options coming in future PR
* Allow repositioning of achievement notifications
* PS4/ORBIS build fix
Would have thought cheevos-related notification code was wrapped in HAVE_CHEEVOS, but guess not.