Syntax Highlighting

Created by: bretthayes

Closes #5251 (closed) and adds syntax highlighting to code blocks in markdown.

Changelog

• added prism rehype plugin to our markdown parsing lib
• added prism-themes and included the prism-one-light theme
• Updated next and mdx-remote
• removed old code element styles
• removed unused font families and fixed our font family declarations
• a few bug fixes in fb0a31b mentioned in this comment

Test

1. Ensure prettier has standardized the proposed changes.
2. Check some post types for syntax highlighting (ie: /blog/graphql/handling-authentication-and-authorization-in-graphql)