Enhanced RabbitMQ email processing by introducing a `SendingEmailConsumerPool` to enable the competing consumers pattern. Each consumer operates on its own channel, improving scalability and thread safety.
- Added `SendingEmailConsumerPool` to manage multiple consumers.
- Updated `DependencyInjection` to register the consumer pool.
- Refactored `SendingEmailConsumer` for better logging and error handling.
- Updated `AsyncInitWorker` to initialize the consumer pool.
- Added `ConsumerConcurrency` to RabbitMQ configuration.
- Improved error handling in `LimilabsEmailService` with detailed SMTP error messages.