Support for macOS pkg publishing

[jeromelaban]

No description provided.

[spouliot]

@dansiegel a tricky part [1] will be to create fat (both x64 and arm slices) executables so the same app bundle can run on any supported Mac computers [2].

[1] Last time I checked the dotnet stub executable is platform specific. You might have to roll your own (from scratch or by lipo'ing the dotnet ones).

[2] that was handled with the "Xamarin" and re-branded MS platforms SDK which create their own executable.

[dansiegel]

requires #17427

[spouliot]

Included in 5.6 (along with package notarization)
Documentation PR