add chunk interval autotune.md

[ggodeke]

Describe your changes

What did you change? Why did you change it?

Related Issues

If there is a related issue, please add it below (just put the number after the # below, and GitHub will automatically create a link):

Issue: #number

Checklist before requesting a review

• - Is this ready for review? If not, raise as a draft PR
• - This has deployed to a staging environment correctly
• - I have reviewed my changes.
• - I have confirmed the content is technically accurate.
• - I have confirmed the content is free of typos or grammar errors.
• - I have reviewed the deployed version of my changes.
• - I have tested any code that is added or updated.
• - I have verified all images and videos are clear, with appropriate zoom.
• - I have verified all images and videos match production (or dev for unreleased features).
• - I have tested that the content matches the functionality in production (or dev for unreleased features).
• - All checks have passed.
• - This references a feature that is public. If not, add a note and we can schedule the merge for after the feature release.

[github-actions]

Allow 10 minutes from last push for the staging site to build. If the link doesn't work, try using incognito mode instead. For internal reviewers, check web-documentation repo actions for staging build status. Link to build for this PR: http://docs-dev.timescale.com/docs-ggodeke-patch-1