svelte and workbox

try to make this work like an offline PWA

key takeaways

• put serviceworker in root / - will save you trouble
• you are suppose to build sw.js separately with bundler (rollup) - and not as a part of your regular build - you can define an array of input/output setups in rollup.config.js or you can have separate config files
• you also seem to need webmanifest file for offline to work. And yes, also cache manifest in the sw