Offline support for the online bundler analyzer

I'm writing up a [little CLI](https://github.com/fabiospampinato/banal) that generates a metafile locally for the given name of an NPM package and loads it on the online bundle analyzer via the url, however it looks like that website is not set up to work without an internet connection. If possible I'd be pretty useful to set that up so that the website is reliably available, even without an internet connection.

The issue names no files, tests, or entry points. Start by locating the online bundle analyzer in the repository and determine how it loads its assets and metafiles; done means the analyzer remains reliably usable without an internet connection, including for the locally generated metafiles described in the issue.

Written by the indexing model from the issue text.