Expand framework support and COM ABI coverage

Target .NET 8, 9, 10, Framework 4.7.2, and Framework 4.8. Rename samples to stable Core and Framework names. Add raw-vtable COM tests for x64, x86, and ARM64, and require the Azure architecture matrix before packaging.

src/Lithnet.CredentialProvider.UnitTests.x64/ComInterop/GetStringValueDelegate.cs

@@ -0,0 +1,8 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Lithnet.CredentialProvider.UnitTests.ComInterop
+{
+    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
+    internal delegate int GetStringValueDelegate(IntPtr instance, uint fieldId, out IntPtr value);
+}