moves the game list model/worker/private stuff to qt_common for later
use in QML
- `qt_common/game_list/model.{cpp,h}` is the model
- `yuzu/game/game_{grid,tree}.*` are the views
- `yuzu/game/game_list.cpp` is the presenter
This was done very lazily in a manner that "works" while largely
maintaining existing structure as much as possible. Most of it is
copy-paste, with some bonus reworks/cleanups thrown in.
Signed-off-by: crueter <crueter@eden-emu.dev>
