[KCM]Update Device item layout based on applet

Summary:
Remove device icon.
Remove separation line between devices and increase spacing.
Use radioboxes for default device selection.
Always allow port selection.
Fix mute tooltip.
Use small spacing instead of default.
Use plasma components 3 instead of qtquick controls 2.
Remove unused imports.

BUG: 417607
CCBUG: 417447
FIXED-IN: 5.19.0

Doesn't depend, but needs D27420 to activate an unavailable port.

Test Plan:
Before:
Was not possible to select an unavailable port.
Combobox could drive the default button out of the layout.
After:
Combobox row appears for devices that have at least two ports.

Reviewers: Plasma, drosca, ngraham, VDG

Reviewed By: ngraham, VDG

Subscribers: davidedmundson, plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D27422