Introduce a human-readable sitemap to the documentation

[KrishnaIyer]

Summary

Introduce a human-readable sitemap to the documentation

Refs: #1394 (comment)

Changes

• Add a new auto-generated sitemap partial.
• Add sitemap link to the footer.

Screenshots

Notes for Reviewers

• We already have a bot-readable sitemap.xml from Hugo. This is a separate page in Human readble format.
• The CLI Reference is a quick fix for a different reported issue.

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Run Locally: Verified that the docs build using make server, posted screenshots, verified external links. Test with HUGO_PARAMS_SEARCH_ENABLED=true if style changes will affect the search bar.
• New Features Marked: Documentation for new features is marked using the new-in-version shortcode, according to the guidelines in CONTRIBUTING.
• Style Guidelines: Documentation obeys style guidelines in CONTRIBUTING.
• Commits: Commit messages follow guidelines in CONTRIBUTING, there are no fixup commits left.