Add DependencyInjection class for service registration

Introduced a new `DependencyInjection` class in the `ReC.Application` namespace to streamline service registration.

- Added `AddRecServices` extension method for `IServiceCollection` to configure AutoMapper and MediatR with assembly scanning.
- Included `ConfigurationOptions` class to allow configuration of a `LuckyPennySoftwareLicenseKey`.
- Added `using` directives for `Microsoft.Extensions.DependencyInjection` and `System.Reflection` to support dependency injection and assembly scanning.

src/ReC.Application/DependencyInjection.cs

@@ -0,0 +1,32 @@
+using Microsoft.Extensions.DependencyInjection;
+using System.Reflection;
+
+namespace ReC.Application;
+
+public static class DependencyInjection
+{
+    public static IServiceCollection AddRecServices(this IServiceCollection services, Action<ConfigurationOptions> options)
+    {
+        var configOpt = new ConfigurationOptions();
+        options.Invoke(configOpt);
+
+        services.AddAutoMapper(cfg =>
+        {
+            cfg.AddMaps(Assembly.GetExecutingAssembly());
+            cfg.LicenseKey = configOpt.LuckyPennySoftwareLicenseKey;
+        });
+
+        services.AddMediatR(cfg =>
+        {
+            cfg.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly());
+            cfg.LicenseKey = configOpt.LuckyPennySoftwareLicenseKey;
+        });
+
+        return services;
+    }
+
+    public class ConfigurationOptions
+    {
+        public string LuckyPennySoftwareLicenseKey { get; set; } = string.Empty;
+    }
+}