Investigate Partition/Chunk loading

[bcarter97]

fs2-kafka added a chunk-based API that partitions a kafka stream and processes different partitions in parallel. It would be good to have the same sort of API for the topic loader, given it works with fs2-kafka and is often used in combination with a normal Kafka stream for post-load streaming.

https://github.com/fd4s/fs2-kafka/releases/tag/v3.3.0