Reducing the number of supported message queue providers

[masci]

As we resume work on the project, we're rolling out several major refactorings. One of the biggest challenges has been maintaining support for a wide range of message queue providers, and it's become a significant burden for us maintainers.

Long-term, our goal is to support a single, default provider and move others into external packages, following a model similar to how LlamaIndex handles integrations.

Short-term, we’re cleaning up by removing broken or poorly maintained providers, while keeping the rest as-is. Tentatively, we plan to continue supporting:

• Redis
• Kafka
• RabbitMQ

We understand this may cause some disruption, and we apologize for that. However, given the current state of some of these integrations, we believe this is the right call to ensure the project remains healthy and maintainable.