Add support for C# WinRT/components in C++ applications

[ocalvo]

In order to support this scenario we may need to support .NET Core 5 or .NET Core 6

[kmelmon]

See #38 which changed the NativeXamlIslands sample from a mixed C++/C# app to just straight C++. As a starting point, we can try to get the version of this project from just before the PR working.

More context on the issue we faced with this version:

The project builds but when deploying to a clean machine without Visual Studio installed, you'll see this error:
Windows cannot install package 99def245-f2b3-46c8-9d9d-2f4780e9e424_1.0.17.0_x64__gw2qmfeskbexa because this package depends on a framework that could not be found. Provide the framework "Microsoft.NET.CoreRuntime.1.1" published by "CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US", with neutral or x64 processor architecture and minimum version 1.1.27004.0, along with this package to install. The frameworks with name "Microsoft.NET.CoreRuntime.1.1" currently installed are: {}

The issue here is that the ".net UWP" package needs to be installed. This package is not the same as .NET Core 3... it's a special version of .net that supports UWP apps, and relies on .net native.

Some links with context on this:

Authoring a C# Windows Runtime component for use from a C++/WinRT app - UWP applications | Microsoft Docs
Error 0x80131040 "The located assembly's manifest definition does not match the assembly reference" when I use a Windows Runtime class written in C# from my C++/WinRT project | The Old New Thing (microsoft.com)
asklar/WinRTComponent: How to consume C# WinRT components from C++ (github.com)
Building C++/WinRT apps that consume C# components | a.rcad.io

[asklar]

FYI @tommcdon @SvetBonev