Update the JS support
Updates the JS support replacing the deprecated engine classes to the new ones available in Qt 5.15+.
It's important to remember that has some of the resources in the old classes that don't have equivalent in the new ones.
The debugger was not able to be replaced, and don't have compatibility with the new usage. So i just gave up it. I think it have to be created again from scratch.
To test, can be used some JS script with arrow function for example or other resource available in the latest JS versions.