klipper: port KlipperPopup to QML

Reason for the change

Let it share UI with the widget to port away from the ancient QWidget look.

• Port services away from dataengine
• Create an image source for previews
• Set a translation domain
• Handle escape and focus loss
• Test on Wayland

Closes #130 (closed)

Test plan

Press Meta+V to open the clipboard menu

Screenshots or screen recordings

Before	After

Bugs fixed