Allow QML function calls from Android code

Why?

I want to be able to call QML functions from Android, either to provide data to the QML view, or to trigger special behaviors, without having to toggle a property to trigger a QML property change listener.

What?

How?

Extend the QtQuickViewContent java class to provide a java -> native function chain to call a function with N arguments.

Extend the qandroidquickviewembedding native code to support above, and then call the QML function.

Extend the code generation in ADQT to also generate Java functions that will call the native functions that call QML functions.

Chain these together, add a test suite.