chore: add workflow to delete preview link

[coelhucas]

This will dispatch another workflow inside web-documentation to delete Amplify previews previously created from a specific branch

[github-actions[bot]]

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-chore-delete-preview-workflow

[billy-the-fish]

Nice