Update native module documentation with NativeModuleSample/cpp-lib

[jonthysell]

Summary

We now have a new cpp-lib NativeModuleSample using the new hybrid old/new template. When possible, we need to update the existing C++ native module sample documentation to reflect the code in this version, and update links.

Motivation

The new hybrid template, while not "officially launched" in 0.76, is the way forward for library developers.

Basic Example

No response

Open Questions

No response

[chrisglein]

Documentation has C++ and C# in parallel, but we're at a time where C# support for new architecture isn't there. So will require some thought about how to show in the docs.