Handle change in default groupId behavior in kafka consumer

[navina]

Starting kafka 2.2.0 onwards, when group.id is not specified in the kafka consumer config, it is set as null, instead of an empty string. Due to this change, even though auto-commit is enabled, it doesn't show up in the consumer offsets topics. This breaks existing kafka monitoring tools.

One proposed solution is for Pinot to set a default group id when it was not explicitly configured by user (say, table name as the default group id).

[navina]

@npawar please tag as beginner-task

[tanmesh]

I am planning to pick this task.

[tanmesh]

Hey @npawar @navina 👋 , can you please assign someone to review this PR 🙏

[pjpringle]

I didn't think pinot should be using Kafka consumer group offset management nor auto.commit as pinot manages it own consumer partition assignment and offsets. Using a group id results in a subset of partitions getting assigned to each instance and stops the replica count from working.