Add project files.

Framework/Core/Configurations/IWritableJsonFileFactory.cs

@@ -0,0 +1,15 @@
+using System.IO;
+
+namespace TheXamlGuy.Framework.Core
+{
+    public interface IWritableJsonConfigurationBuilder
+    {
+        Stream? DefaultFileStream { get; }
+
+        IWritableJsonConfigurationBuilder AddDefaultConfiguration<TConfiguration>(string Key) where TConfiguration : class;
+
+        IWritableJsonConfigurationBuilder AddDefaultFileStream(Stream stream);
+
+        void Build(string path);
+    }
+}