[moetemp]

What was changed

This PR adds the Stream examples, the end-to-end Redis tests, the Streams module doc of temporalio.common, the Streams changelog fragment and a CODEOWNERS entry.

• Each example follows the Python tab of its API proposal section, and runs as a test on both backends. A Workflow hands out its Stream through a stream query.
• The end-to-end tests cover Workflow and Activity writes to one Stream, replays, codecs, eviction, retries, continue-as-new and two backends on one client.
• worker_setup.py says that a Worker serves only one backend. Its test checks that a Worker on the migration's client with two backends raises StreamConfigError.
• The changelog fragment covers the whole stack, so S1 to S8 have none.

Depends on S8 (#378).
Part of the Brook review series.

Why?

After this PR, moe/brook/review/feature-streams has the whole API. Upstream merges feature/streams into main once, so main never has half an API. The examples are the API docs until the docs site has Streams.

Open question. CODEOWNERS names the AI SDK team and the SDK team for the Streams paths. Which team owns them?

Checklist

1. How was this tested:
   • poe lint, poe bridge-lint, poe gen-docs, the check-protos steps, and the Worker, client, Workflow, Nexus, converter, bridge and Streams suites. The Streams tests also ran with protobuf 3.20, as check-protos does.
   • Fork CI passes, except the arm jobs, since the fork has no arm runners. The Redis lane runs on Redis 7.0 (Ubuntu) and Redis 8 (macOS).