Add CreateOutResCommand class for handling output results

Introduced the `CreateOutResCommand` class in the `ReC.Application.OutResults.Commands` namespace. This class includes properties for managing output results, such as `ActionId`, `ResultHeader`, `ResultBody`, and `AddedWho`. Added a static readonly `EmptyJson` property for initializing JSON fields with a serialized empty object. Included `System.Text.Json` for JSON serialization functionality.

src/ReC.Application/OutResults/Commands/CreateOutResCommand.cs

@@ -0,0 +1,19 @@
+using System.Text.Json;
+
+namespace ReC.Application.OutResults.Commands;
+
+public class CreateOutResCommand
+{
+    public static readonly string EmptyJson = JsonSerializer.Serialize(new object(), options: new()
+    {
+        WriteIndented = false
+    });
+
+    public long ActionId { get; set; }
+
+    public string ResultHeader { get; set; } = EmptyJson;
+
+    public string ResultBody { get; set; } = EmptyJson;
+
+    public string? AddedWho { get; set; }
+}