Removed webpack dependency

• Removed import 'style.css' to not have dependency of webpack.
• Added styles.scss to have all styles in one file.

Components by demand

• Components could be imported by demand
• Updated eslint to eslint-config-vizzuality
• Removed webpack as asset compiler
• Using gulp to copy files in dist folder
• Using babel to transpile es6 files in dist folder
• Updated package tasks
• Story book use his own webpack configuration