Windeployqt does not deploy QtQuick WebEngine module

`windeployqt` doesn't deploy QtQuick + WebEngine applications correctly.

Although most of the WebEngine dependencies are deployed, the Quick Module is missing. My deployed application freezes when trying to create a WebView.

After manually copying the `qml\QtWebEngine` and `qml\QtWebView` folders from the Qt Kit to the application folder the application works as expected.

Windeployqt seems to pick up all the right dependencies since a custom qml plugin I use is also found and deployed, but it just "forgets" to deploy the WebEngine module.

EDIT: As far as I remember this was working at some point in the past. So this might be a regression.