Message broker requirements

[mocsharp]

Defines message broker requirements for the MONAI Deploy platform.

[dbericat]

Not trying to get into the solution space at all, but good readings to come up/validate requirements about event-driven architectures with (arguably) the most used one, Kafka:

1. https://dzone.com/articles/microservices-event-driven-architecture-and-kafka
2. https://www.confluent.io/blog/apache-kafka-for-service-architectures/ (The whole series is fantastic. It starts on https://www.confluent.io/blog/data-dichotomy-rethinking-the-way-we-treat-data-and-services/)

P.S. And yes, it scales up to trillions of messages if we needed to. Which I doubt. :) https://engineering.linkedin.com/blog/2019/apache-kafka-trillion-messages