DOC-5189 Multi-region CDC in the Astra Portal

[aimurphy]

Recreation of https://github.com/riptano/docs-common/pull/75 after moving the CDC for Astra content into the Streaming docs exclusively.

https://d5rxiv0do0q3v.cloudfront.net/doc-5189/astra-streaming/developing/astream-cdc.html

[plpesvc-ds]

Build successful! ✅
Pull requests with matching branch name doc-5189 included in the build:

• DOC-5189 Multi-region CDC in the Astra Portal #150 (this pull request)
• https://github.com/riptano/astra-vector-docs/pull/1127

Deploying draft.
Deploy successful! View draft

[plpesvc-ds]

The draft build for this pull request has been cleaned up due to being stale.

Draft builds 2 weeks old or older were automatically removed.

You can rebuild the draft at any time by pushing a new commit to this pull request:

git checkout doc-5189
git commit --allow-empty -m 'rebuild draft'
git push origin doc-5189