Migrate to docusaurus

[jeluard]

Migrate existing docs (using mkdocs) to docusaurus. Find details about the rationale here.

Following items have to be done:

• Migrate to docusaurus #6533
• Reconsider documentation website layout #6550
• Add versioning support to documentation website #6548 (see chore: prepare for docs versioning #6559)
• Add analytics support to documentation website #6549
• Optimize SEO for documentation website #6547
• Experiment with light-client in docusaurus #6575
• chore: fix documentation CLI #6566
• chore: customize docusaurus title #6560

Link redirection

Docs are currently hosted as gh-pages. If we keep this hosting, redirect will have to be handled at the website level (as opposed to HTTP level).

• https://docusaurus.io/docs/api/plugins/@docusaurus/plugin-client-redirects

Resources

• https://handbook.chainsafe.io/development/documentation/
• https://github.com/lerna/lerna/tree/main/website
• https://github.com/Consensys/doc.teku
• https://github.com/risc0/risc0/tree/main/website
• https://github.com/facebook/docusaurus/tree/main/website

[philknows]

Related #5961

[wemeetagain]

closing as complete