Backport path fixes for self-hosted docs sites to 16.7

What does this MR do and why?

Backports the fixes in !4598 (merged) to 16.7:

• Fixes Lunr search result URLs
• Fixes the link to the homepage from the logo
• Fixes the link to the latest version from the "archived version" banner

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

See !4635 (merged). Adjust version number accordingly.

Merge request acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this merge request.