Update to docusaurus 2

website/docs/markdown-features.mdx

website/docs/thank-you.md

website/docusaurus.config.js

website/package.json

website/pages/en/help.js

website/pages/en/index.js

website/pages/en/users.js

website/sidebars.js

website/sidebars.json

website/siteConfig.js

website/src/css/custom.css

website/src/pages/index.js

website/src/pages/markdown-page.md

website/src/pages/styles.module.css

website/static/.nojekyll

website/static/css/custom.css

website/static/img/docusaurus.png

website/static/img/favicon.ico

website/static/img/logo.svg

website/static/img/oss_logo.png