Add support for qml live editing

Live editing is the standard for pretty much every modern ui toolkit. It would be great if this vscode extension also would offer this:

• Change existing properties like text color. This should be easily doable
• Support for changing (reloading?) qml code

There are different ways to implement live reloading:

1. Live reloading where you wrap a qml item in a Loader and simple force a full reload. This would require application support and thus not the way to go
2. Sending the qml engine update instructions, based on the current qml code model of the altered file.