[Feature Request] Add a cli option to change the window class or app_id

[sga-13]

Description: Allow changing the app_id (wayland) or class (x11) or window_id (mac i think, not sure) (dont know about windows equivalent) for a window. This can allow to programatically categorise or place windows, for example, in my wm config, I can set to move all windows with app_id scratch_terminal to the scratch pad, or floating_terminal to be floating. Ideally this app_id should be configurable per window (and not per instance).