Compatability with ES6 Modules

** Context **
The current repo is used by dweb-mirror via Node, and dweb-archive via webpack.
Both of these are happy with "require"

However, Jason wants to use it with ES6 Modules, and that only works with `import`

**Proposal and Constraints**
Change all require's for import and fix any problems that arise

**Success Metrics**
If Jason can import dweb-archivecontroller/ArchiveItem, ArchiveFile, ArchiveMember into his Lit based web components.
AND
We can still successfully include it by running `webpack --mode production` in dweb-archive repo,
AND successfully include it by running "internetarchive -sc"
i.e. this solution should include PR's in both those repo's if required.

**Stakeholders**
@jbuckner @mitra42

**Resources and Links**
https://timonweb.com/tutorials/how-to-enable-ecmascript-6-imports-in-nodejs/ describes how to use esm to run import in Node