🚨 Fix Linter Warnings (#990)

[mistryrn]

Bring codebase up to modern eslint spec, fixing over 100 new linter warnings from the eslint/prettier upgrades:

• Update eslint config from .eslintrc.js to .eslintrc
• Change all unnamed default exports to named default exports
• Prettier fixes for css declarations, long lines, conditionals, indentation, etc