PWA for app refreshes

[baetheus]

Currently app upgrades happen when the page refreshes. When the puzzle list changes (which should now be rare), this can cause a puzzle to disappear while someone was working on it.. Baaad. Ideally we should use a webworker to for reload the page when new versions are detected.

[baetheus]

For service worker let's not go too deep: https://developers.google.com/web/tools/workbox/modules/workbox-cli

[baetheus]

Goals:

• Mark app as a PWA that is installable
• Use cache then fallback to network for file access
• Be sure that app start checks for app changes and and reloads if necessary
• For long running apps periodically check for changes and reload if necessary
• New icon for bee - maybe get https://hoodzpahdesign.com/ in on it