Bugfix/blog multi authors

Created by: st0nebraker

Closes #5328 (closed) to allow multiple authors on blogposts along with the authors url.

NOTE

• Focus on these 4 files. The other 400+ are just reference updates

• Accompanying PR to update Handbook blog post instructions: Handbook PR#3491
• Happy to sit on this PR for a few days if the team thinks it'll be too cumbersome to deal with the merge!

TEST

• Nav to /blog/real-weakest-link-in-software-supply-chain-security/ and ensure multiple blog authors are supported
• Ensure no breaking changes for other blog posts

BEFORE:

NOW: