Next.JS with Notion API

• Cleaner version implemented with Next.JS
• Blog contents are powered by Notion API

New material-ui style, test, and content

• Update material-ui from v3 to v4.
• Update testing from using react-scripts to jest and enzyme.
• Update contents on the site.
• Change font family from Roboto to Adobe Source Code Pro.
• Rearrange sections.

1.0

Update Main.js