Add compliance with full PWA standards

[JSKitty]

Abstract

As part of the on-going MPW interface redesign for a "mobile-first" era, MPW additionally needs full compliance with Progressive Web App standards.

As such, when the two above features are combined, MPW will become a fully install-able, standalone application on a vast majority of devices, and the ability to distribute MPW as an actual application on App Stores becomes vastly easier.

Things to do

• Complete responsiveness adaptation for mobile. (Starting with New dashboard design and responsive! #73)
• Comprehensive research in to PWAs and their specs.
• Compatible icon sets, graphics and splash-screens.
• Handle offline devices better, f.e: display notices, auto-reconnect once back online, etc.