Webpack env update

[ruiposse]

• Create webpack.frontend.base.config.babel.js
• webpack.frontend.dev.config.babel.js
  • "extends" webpack.frontend.base.config.babel.js
  • sourcemaps
• Create prod webpacks:
  • uglify (frontend, backend)
  • frontend: app.js and vendor.js ?
  • webpack.frontend.prod.config.babel.js
  • webpack.backend.prod.config.babel.js