Enhance framework compatibility and code readability

Added preprocessor directives for .NET framework compatibility.
Modified `using` directives to be framework-specific.
Improved code formatting for better readability.
Introduced obsolete attributes for deprecated methods,
recommending `MediatR` as an alternative.
Added XML documentation for clarity and maintainability.

DigitalData.Core.Abstraction.Application/DTO/DIExtensions.cs

@@ -1,4 +1,5 @@
-using Microsoft.Extensions.Configuration;
+#if NET
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using System.Configuration;
 
@@ -31,4 +32,5 @@ public static class DIExtensions
         });
         return services;
     }
-}
+}
+#endif