Add Algolia search

[lukekim]

• https://www.docsy.dev/docs/adding-content/navigation/#configure-algolia-docsearch
• https://forestry.io/blog/search-with-algolia-in-hugo/

[ewgenius]

I've applied for Algolia search
https://docsearch.algolia.com/docs/who-can-apply/
https://docusaurus.io/docs/search#using-algolia-docsearch