Evaluate Nuxeo Stream implementation on Apache Pulsar

Apache Pulsar is a messaging system that can be used in place of Kafka. In addition to the Log abstraction it also provides a pattern for simple message queue which could be very interesting to address scalability cases where:

• there is no causality between messages (no ordering)
• we want to scale without limit (independently of the number of partitions)
• with an optimal load balancing

There is a drop-in jar that would allow existing Producer/Consumer Kafka applications to use Pulsar without code changes but Nuxeo also uses administrative APIs for Kafka, so it might not be enough.

The goal of this ticket is to evaluate the necessary work to have Nuxeo Stream implementation based on Pulsar,
and learn how to leverage the new possibilities.

Note that several customers and prospects have moved to Pulsar.