gulp based frontend pipeline

[maizy]

• gulp
  • npm deps
  • less
  • babel
    • import statements transpiler
  • https://github.com/google/web-starter-kit/blob/master/gulpfile.babel.js
• frontend subproject (?)
• run in dev env, with server/run
• sbt->gulp integration
  • https://github.com/timcowlishaw/sbt-gulp
  • ... google: sbt gulp
• airbnb js style guide - https://github.com/airbnb/javascript
  • eslint checker