Remove ytdl requirement and rewrite/cleanup the code

[brecert]

• add flake files for nixos development
• changed node require imports to esm imports
  • changed the modules type to module to enable esm imports
• replaced ytdl with handwritten js twitter client
  • added node-fetch as a dependency for the twitter client
• cleaned up the code and rewrote much of it
  • added basic jsdoc type annotations for typescript type hints
  • added tsconfig.json to enable type hints
  • replaced both twitterURLRegexs with a single `TWITTER_URL_REGEX
  • modified the url match code to be more compact
  • modified to be fully async by using Promise.all
• fixed a bug where links were not delimited by any characters when joining
  • join now uses '\n'