move away from deprecated QTScript to QJSEngine based scripting
QTScript is deprecated since QT 5.5 (?), recommended alternative is QJSEngine. Problems with moving away are:
- QTScript systems are present in interfaces -> interfaces will have to change
- As a result of this, plugins using the scripting system have to be touched
First step: Abstract direct usage of QTScript classes in usage code (i.e. PropertyVisPlugin) to find suitable new abstraction When this is done, make all usage code use new abstraction, then incrementally port internals to QJSEngine.