Port plasma desktop scripting to qjsengine, removing every trace of QScript from plasma-workspace.
The scripting is 100% API compatible.
- setting AppInterface as the globalobject's proto with property getters that are evaluated every time
- setting functions that act as constructors (using newQMetaObject gives way more complex and uglier c++ code in Containment, as the scriptengine is not immediately accessible)
- a QRectF wrapper which exposes all properties and methods that were exposed in the previous implementation