enhancement(nats source): add support for NATS JetStream (#23554)

* feat(nats source): add jetstream support

* refactor: create helper function for shared message logic

* chore: explicitly set batch config defaults

* refactor: split nats source in directory

* chore: add tests for jetstream

* chore: reorganize import order

* chore: improve readability of build using mode enum

* chore: enable acknowledgment

* chore: properly set batch config

* chore: add jetstream docs

* chore: add missing const function

* docs: add changelog fragment

* chore(ci): add nats source to semantic

* chore: derive jetstream docstring from config struct

* fix: remove double module definition for tests

* chore: fix merge conflict

* chore: fix formatting

* fix: formatting

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Co-authored-by: Pavlos Rontidis <pavlos.rontidis@gmail.com>