Dynamic sharding Jetstream streams

[AbstractiveNord]

Proposed change

Apply dynamic sharding for Jetstream streams.

Use case

In general, it's very often case, when you replace one node to another, and you want to have an API for remove node from cluster, which should cause subject change and data transfer procedures, add node into cluster, which also should cause same changes, etc. It's good to have a high level tool for that job.

Contribution

Yes.