kcms/display: Restore and port to libkscreen and new components

Devin Linrequested to merge
work/devinlin/display into master

This restores the display KCM, now with the backend rewritten to use libkscreen and ported to the new KCM components.

This also adds a ComboBoxDelegate component to the controls.

This adds a dependency to libkscreen.

Screencast_20250624_110648

Edited by Devin Lin

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