Announcing Reunion2

[wjk]

We were promised source code for WinUI 3 years and years ago, and not one line of it has hit GitHub yet. Your continued excuse "it'll take a while, but we're working on it! pinky swear!" is wearing really, really thin. Therefore, I have forked the Windows App SDK as a concept into this repository: https://github.com/wjk/Reunion2.

It currently contains the source code for cppwinrt.exe, and a much easier-to-read props/targets file. I was planning on next creating a VS extension with improved C++/WinRT project and item templates, as declined upstream, but the changes to third-party extension integration in VS2022 have thrown a bit of a wrench into that plan. Going forward the open-source components of the App SDK will be copied into this repo and reorganized. As for the closed-source components of the App SDK, I will use build-time logic to extract the relevant binaries from Microsoft's NuGet and MSIX packages and massage them into an easier-to-use format.

I am fully open for third-party contributions to this project.