Improve the track list scrolling speed, better trackpad scrolling

Summary:
There's an issue when scrolling with a list view on a trackpad:

https://bugreports.qt.io/browse/QTBUG-56075

With this patch scroll momentum is disabled for desktop but overall I think it provides a better experience.

Further scroll performance is greatly improved, see these comparisons!

Slower scroll:

Faster scroll:

Reviewers: camiloh

Reviewed By: camiloh

Differential Revision: https://phabricator.kde.org/D13877