Draft: plugins: add windowvibrate effect
This internal effect makes selected window vibrate for a short time on request.
You can request the effect by: window->effectWindow()->setData(WindowVibrateRole, "reason");
The window will vibrate for a short time and then stop. The data is cleared
after the effect stops.
The intention is to use this effect as a visual feedback when a kwin shortcut results in no-op. For example, when trying to move a window to a screen to the left, but the window is already on the leftmost screen.
Demo:
We might need an option in the accessibility KCM to disable this effect.