Clean up code style stuff throughout the app

[knod]

We'll use our current understanding of the code style for now. Further discussions can be had if needed, but they'll be saved for future changes.

Maybe we can use this opportunity to make an explicit style guide.

Assume '/src' comes before all these directories. Some directories still need to be broken up into smaller chuncks.

• [x] /components
  • [x] /dev for @knod
  • [x] /prompts for @knod
  • [x] through ExternalLink.js for @knod
  • [x] through headings.js for @knod
  • [x] through Surrounder.js for @knod
• [x] /containers
• [x] /data
• [x] /forms
  • [x] /output
  • [x] others
• [x] /localization?
• [x] /programs
• [ ] /utils
• [x] App.js
• [x] index.js
• [x] index.css (!important, etc)