research: Swift Cxx interoperabiliy

[tony-go]

As preleminary work, I did research arround Swift/Cxx interoperability aiming to see if we could enforce the usage of Swift for our Apple supported platforms.

I tried to implement a basic framework with Swift and Cxx here: https://github.com/tony-go/native-research

I faced two issues:

• I struggle to consume a Swift module from another while interoperability is enabled. I asked help here: How to consume Swift modules when Cxx interop is enabled apple/swift-cmake-examples#15

• I don't know how directly conform a Swift class to a C++ one. I asked help here: https://developer.apple.com/forums/thread/751158 - My current workaround was to create an intermediate C++ file but I wonder if on the end it won't result to a lot for boilerplate.

The second issue is probably the most important.

We should continue to research but I think that starting with C++/Objective-C++ is prolly better at first.