Consider allowing components to share cached resources

[mpeterdev]

By default, importing npm packages from a CDN cause the package to be fetched over the network by every component instance that imports it. This is due to the iframes not sharing cached resources. It can cause significant request overhead

e.g. rendering a social feed with a post level component which imports a package to convert markdown to jsx requires a fetch of that markdown conversion package for every single post in the feed

changing behavior to share a cache presents a privacy risk as detailed here: https://www.jefftk.com/p/shared-cache-is-going-away