fix: use less indexedDB in service worker #810
Description
reading from indexedDB in the service worker causes a slight performance hit, but we should be able to store state in a service worker response cache.
We have a few different places where we need to load the config (hits IDB) or get the installTimestamp, or accept origin isolation warning, or potentially others.
This may be called on every new fetch event, but we can get a minor speedup and reduce SW bundle size by migrating away from indexedDB and using a response cache.
This should improve coldstart (firsthit) by at least a few 10s or 100s of milliseconds.