[Docs] Add deprecation notice for MacOS x86_64 builds

[florent-leborgne]

This PR adds a deprecation notice to the release and upgrade notes regarding macOS x86_64 builds.

+a small fix of reordering deprecation and breaking changes correctly in 8.16 release notes

[elasticmachine]

Pinging @elastic/kibana-docs (Team:Docs)

[github-actions[bot]]

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[florent-leborgne]

💚 All backports created successfully

Status	Branch	Result
✅	8.17
✅	8.16

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