[8.17] Elastic Rerank model landing page (backport #2884)

[mergify]

• Initial drafting happened in shadow Google Doc

URL preview 🔭 👁️

TODO

• Air-gapped deployment instructions (possibly in follow-up PR)

  ---

  This is an automatic backport of pull request Elastic Rerank model landing page #2884 done by Mergify.

[github-actions]

A documentation preview will be available soon.

• 🔨 Buildkite builds
• 📚 HTML diff
• 📙 Preview page

Request a new doc build by commenting

• Rebuild this PR: run docs-build
• Rebuild this PR and all Elastic docs: run docs-build rebuild

_{run docs-build is much faster than run docs-build rebuild. A rebuild should only be needed in rare situations.}

_{If your PR continues to fail for an unknown reason, the doc build pipeline may be broken. Elastic employees can check the pipeline status here.}