Upgrade Deps

[yassernasc]

Bundle of updates, nothing new yet but it will help to continue the development

• Updated react's version to 16.14 (which allow us to write hooks);
• Enabled the new jsx transform (so we don't need to import react to use jsx anymore);
• Since Radium is now deprecated and it doesn't seem to work well with new react versions and hooks, I've migrate the styles to emotion, that has a pretty similar API;
• To make emotion work, I had to upgrade the babel's packages as well. Now using the @babel/preset-env for polyfills, that consumes the browserslist config;
• Upgrade webpack to latest. Now using the --mode arg instead NODE_ENV;
• Upgrade electron's version to 12.