Created by: endiliey
Motivation
Bump docusaurus 2 to latest version. There are lot of improvements such as smaller client bundle size, better a11y, better dark-mode, line highlighting, etc and so on. Can check full changelog here https://github.com/facebook/docusaurus/blob/master/CHANGELOG-2.x.md
I also tweaked the CSS abit.
One thing I notice too is that Algolia docsearch has never been updated from algolia side, so its appending weird #docsNav (legacy of v1). I sent a PR to docsearch for update
Don't merge yet until https://github.com/algolia/docsearch-configs/pull/1165 land.
https://deploy-preview-8111--create-react-app.netlify.com/
Test Plan
