QML mouse cursor KCM and components

Summary:
introduce a cursor theme kcm ported to QML, following the new
design guidelines, alongside generic components that will be reused for
modules that are mostly big grid views, such as look and feel.

BUG: 375106

Test Plan: tested on different devices with different dpi

Reviewers: #plasma, hein

Subscribers: hein, davidedmundson, aspotashev, januz, ngraham, romangg, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D8692