Wayland: Allow to set a scroll Factor for input devices

Summary:
Mouse and touchpad wheel events are concerned.

CCBUG: 403843

KCM patch: D28331

Test Plan: build, ctest, manual set of scrollfactor value via qdbusviewer

Reviewers: KWin, davidedmundson, zzag, bport, ervin, apol

Reviewed By: KWin, davidedmundson, ervin, apol

Subscribers: apol, kwin

Tags: KWin

Differential Revision: https://phabricator.kde.org/D28310