Add sns link and describe changefeed_creation_timestamp function

[kathancox]

Fixes DOC-11479

This PR adds:

• a link to a blog on connecting CRDB changefeeds to Amazon SNS.
• further description to the changefeed_creation_timestamp() function.
• updates wording on the cdc overview page.

v24.2 + v24.3.

[github-actions[bot]]

Files changed:

• src/current/v24.2/cdc-queries.md
• src/current/v24.2/change-data-capture-overview.md
• src/current/v24.2/changefeed-sinks.md
• src/current/v24.3/cdc-queries.md
• src/current/v24.3/change-data-capture-overview.md
• src/current/v24.3/changefeed-sinks.md

[netlify[bot]]

✅ Deploy Preview for cockroachdb-interactivetutorials-docs canceled.

Name	Link
🔨 Latest commit	9027c6f49120a6dc72887da16bb5b7c008d548b4
🔍 Latest deploy log	https://app.netlify.com/sites/cockroachdb-interactivetutorials-docs/deploys/67352422d85045000890bc40

[netlify[bot]]

✅ Deploy Preview for cockroachdb-api-docs canceled.

Name	Link
🔨 Latest commit	9027c6f49120a6dc72887da16bb5b7c008d548b4
🔍 Latest deploy log	https://app.netlify.com/sites/cockroachdb-api-docs/deploys/67352422b2c03100089189ec

[netlify[bot]]

✅ Netlify Preview

Name	Link
🔨 Latest commit	9027c6f49120a6dc72887da16bb5b7c008d548b4
🔍 Latest deploy log	https://app.netlify.com/sites/cockroachdb-docs/deploys/673524227f29d600089c4ac2
😎 Deploy Preview	https://deploy-preview-19114--cockroachdb-docs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.