[PWA] Use Workbox instead of sw-precache

Created by: Sgiath

It would be nice to use Workbox instead of sw-pracache for genrating service-worker.js file since it is officially supported by Google and has more features than sw-pracache. It has also official Webpack plugin so integration shouldn't be hard. Some more info about Workbox is here https://developers.google.com/web/tools/workbox/