[Serverless][8.16] New notes experience - Impacted screenshots and misc updates

[nastasha-solomon]

Summary

Finishes the remaining work needed to resolve #5441 and also:

• Makes minor adjustments to the Notes docs (one of them being the TOC placement of the Notes page in the Serverless docs)
• Does some post-migration Serverless docs cleanup

ESS previews

• Timeline
• Timeline templates
• View detection alert details
• Launch Timeline from investigation guides

Serverless:

• Investigation tools - Added notes as one of the tools users can rely on when investigating events
• Timeline
• Timeline templates
• View detection alert details
• Launch Timeline from investigation guides

[github-actions]

A documentation preview will be available soon.

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[jmikell821]

So many image changes! Thanks for pulling this together!