nimqt - bindings to Qt

[jerous]

@grd I haven't looked into the ".ui" files yet in nimqt. But I think parsing 
the .ui files is not a good idea -- it looks complex, the file format might 
change, and maybe not everything is possible using our nim bindings. One 
approach is to use a macro that uses QUiLoader 
(<https://doc.qt.io/qt-6/designer-using-a-ui-file.html#run-time-form-processing>).
 At compile time it parses the .ui file to know which objects there are, and 
then at run time load them and use `findChild` to assign the objects.