Refactor and enhance JSON handling with extensions

Refactored `ConfigExtensions.cs` to move `ConfigurationExtensions`
to the `ReC.API.Extensions` namespace and re-added the
`GetFakeProfileId` method. Introduced `JsonExtensions.cs` with
a `JsonToDynamic` method for recursive JSON deserialization,
simplifying nested JSON handling. Updated `OutResController.cs`
and `RecActionController.cs` to use the new `JsonToDynamic`
method, improving code readability and reducing duplication.
Overall, modularized and cleaned up code for better maintainability.

src/ReC.API/Extensions/ConfigExtensions.cs

@@ -0,0 +1,6 @@
+namespace ReC.API.Extensions;
+
+public static class ConfigurationExtensions
+{
+    public static int GetFakeProfileId(this IConfiguration config) => config.GetValue("FakeProfileId", 2);
+}