RID aware .NET tools

[tannergooding]

Today, .NET tools always target "any" and as such cannot trivially support scenarios such as https://github.com/dotnet/ClangSharp where native dependencies need to be bundled.

For https://github.com/dotnet/ClangSharp in particular, the tooling has a dependency on libClang and libClangSharp and thus needs to have some mechanism to bundle these dependencies for win-x64, win-arm64, linux-x64, and macos-x64 at a minimum.

It's worth noting support for RID specific tools would likewise allow support for AOT scenarios.

Ideally such support would also support the runtimes.json functionality so that you can have a "meta package" that then only downloads the required RID specific tool for a particular platform. This would reduce the size of NuGet packages for the common scenario.

[hansmbakker]

(comment removed as I understood that this issue focuses on dotnet tools rather than the wider dotnet sdk and tooling)