Ability to set scroll speed in system settings

I hope this is the right place for this issue.

What I want is to be able to set scroll speed in the system settings. This needs to be handled by the desktop environment / toolkit according to https://gitlab.freedesktop.org/libinput/libinput/issues/185

Since this is (from my understanding) about communication between systemsettings (like from GNOME or KDE) and a toolkit (like Qt or GTK) it is probably good to have all parties on board, so it works with as many combinations as possible, maybe by introducing a standard way of communicating said setting(s).

Corresponding toolkit issues:

• gtk#1641
• https://bugreports.qt.io/browse/QTBUG-73467

Corresponding desktop environment issues:

• https://bugs.kde.org/show_bug.cgi?id=403842
• https://bugs.kde.org/show_bug.cgi?id=403843

Corresponding compositor issues:

• mutter#551

Corresponding compositor protocol issues:

• https://gitlab.freedesktop.org/wayland/wayland/issues/87