Interop Marshalling moved

[AaronRobinsonMSFT]

The Interop Marshalling topic should be moved to the more general .NET Guide. See dotnet/coreclr#19090 and dotnet/coreclr#19082.

This topic is relevant to both .NET Framework and .NET Core. There are some minor differences on .NET Core when on Non-Windows platforms, but largely the same when either runtime is on Windows.

cc @jkotas

[jkotas]

There are some minor differences on .NET Core when on Non-Windows platforms

The C++ exception interop is not supported on non-Windows platforms. We should document this. https://github.com/dotnet/coreclr/issues/19192 has details.