Remove RabbitMQ messaging functionality

The application no longer uses RabbitMQ for command publishing and consumption. This commit removes all RabbitMQ-related code, including:

- Removed RabbitMQ service registrations in `DependencyInjection.cs`.
- Deleted `RabbitMqCommandConsumer.cs`, which implemented a background service for consuming commands.
- Deleted `RabbitMqCommandPublisher.cs`, which implemented a publisher for RabbitMQ-based commands.
- Removed RabbitMQ-specific properties (`ExchangeName`, `QueueName`, `RoutingKey`) from `RabbitMqConfiguration.cs`.

These changes reflect a shift in the application's messaging strategy or architecture.

src/DigitalData.EmailProfiler.Infrastructure/DependencyInjection.cs

@@ -37,12 +37,6 @@ public static class DependencyInjection
         services.Configure<RabbitMqConfiguration>(
             configuration.GetSection(RabbitMqConfiguration.SectionName));
 
-        // --- RabbitMQ Command Publisher ---
-        services.AddSingleton<ICommandPublisher, RabbitMqCommandPublisher>();
-
-        // --- RabbitMQ Command Consumer (Background Service) ---
-        services.AddHostedService<RabbitMqCommandConsumer>();
-
         // --- Data Protection (for encryption) ---
         services.AddDataProtection()
             .PersistKeysToFileSystem(new DirectoryInfo(@"C:\ProgramData\EmailService\Keys"))