EPIC | progressive web app (PWA) support

[sojeri]

add support for PWA

I kinda want to save this like an app on my phone, so some s#$%'s required

basic requirements for MVP

data layer

• [ ] implement service worker & simple retry logic (every 6-8 hours?)
• [ ] update fallback weather logic
• [ ] add manifest file

view layer

• [ ] add last queried weather status
• [ ] implement a sweet, sweet favicon

stretch goals

data layer

• [ ] add cache invalidation / retry logic: query once every 4-6 hours or 30min after sunset / before sunrise, whichever comes first

view layer

• [ ] display current time (local to query location)