"Welcome / Quick setup" dialog for feature alternatives

[shenlebantongying]

There are various features in GD that have alternatives

• Colour -> Light vs "Dark Reader"
• Popup -> "To popup" vs "always to main window"
• Collapsing -> "Session collapse" vs No [Feature Request] Add option to auto-collapse dictionaries #115
• Tabbing (unimplemented) -> "One dict per tab" vs "All dict in one tab"
• Portable (?)
• GUI Scaling (poorly implemented) -> "small icons" vs normal vs (does't exist) larger (Btw, shortcuts that nobody knows Alt + plus and Alt + minus exists.)
• Opt-in Wayland breakages (in future) -> Remove scanPopup and global hotkey in Wayland.
• ...

Maybe we need something like below, so that when open GD for the first time, a dialog will pop up for quick settings

I think Light/Dark mode and Tabbing must be there.

Also move the welcome page to the dialog, so that after choosing to "don't show this dialog again", that page won't be loaded for every startup.

KDE's quick settings https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/348

GIMP's and Inkscape's welcome page: