Support for "Kafka queues" aka "share consumers"

See this blog post for more details: https://medium.com/@andrew_schofield/queues-for-kafka-ready-for-prime-time-988f5c58b8f7

This is just to track whether any special work is necessary for the Kafka component to add support for "share consumers" or queues.

Is this something worth adding support for in the Kafka pubsub component?

Start by reading the linked blog post and examining the Kafka pubsub component to determine whether "share consumers" require special work. The issue does not name files or tests; done is an informed decision about whether this support is worth adding and what scope it would have.

Written by the indexing model from the issue text.