Remove usages of QQmlV4Function wherever possible

QQmlV4Function allows passing arbitrary parameters from C++ to a QML function. In most cases, we are however not interested in arbitrary parameters, but a fixed set of them. In those cases, using normal C++ overloads and letting the engine select the correct one is preferable:

1. The engine is able to do expected conversions, if they become necessary
2. Both the compiler and to a lesser extent qmllint/qmllsp cannot handle QQmlV4Function

The main remaining use case for using QQmlV4Function should be accepting an arbitrary number of JS object arguments. For that, we currently lack a good alternative.