refactor/migrate-to-doks

[salmad3]

Context

Migrates docs.libp2p.io from the Hugo Learn theme to the Hugo Doks theme.

• Landing page will better designed and updated in follow-up PR.
• Will request some icons and libp2p-based graphics for the docs site from Crcle, including a cleaner "docs logo".
• "Notices" turned into comments for now.
• Tabs to be readded when upgrading to Docs-starter.
• CI (+ lint checker) and README updated to reflect config.
  • ~Need access to Fleek account to update.~
• While going through the docs again, I came across a lot of opportunity to update the current material which we'll do so right after.
• Includes necessary redirects and link updates.
• ~Top-level "Guides" section to be when we include more guides.~
• Proposing to have reference on the Menu/Navbar as the current reference material just includes references.

Latest preview

Please view the latest Fleek preview here.

[filecorgi]

• I optimized some images for you! See the commit with the comment Automatically optimized images [ci skip]. in this PR for details.
• Hugo build was successful!

[p-shahi]

Looks like the fleek preview is broken, as you suggested in DMs, we could have a beta site for this migration

[salmad3]

We're going to transfer the config from the PL Fleek account to the DaaS Fleek account shortly.

[p-shahi]

I missed this in my last review but this PR still contains some leftover assets from the Doks like images/doks.png, images/screenshot.png, and images/tn.png

[p-shahi]

I see the preview is here now: https://libp2p-docs-beta.on.fleek.co/ Looking good, will review it too

[salmad3]

The main site build is now updated with the same configuration as the beta site.