Refactored the RabbitMQ-based email queue system by splitting
`OutgoingEmailQueue` into `OutgoingEmailPublisher` and
`OutgoingEmailConsumer` to separate publishing and consuming
responsibilities.
- Introduced `IOutgoingEmailConsumer` and renamed
`IOutgoingEmailQueue` to `IOutgoingEmailPublisher` for clarity.
- Updated `SendEmailCommandHandler` to use the new publisher
abstraction.
- Added `RabbitMqConnectionFactory` to centralize RabbitMQ
connection management.
- Updated dependency injection to register new services.
- Simplified RabbitMQ initialization logic by delegating it to
`RabbitMqConnectionFactory`.
- Enhanced logging for better observability.
- Improved modularity and maintainability by separating concerns
between message publishing and consuming.
