Add test to aggregate external javascript files

This test would find any externally loaded javascript files, e.g.

document.querySelectorAll("script[src^=https]").forEach(s => console.log(s.src))

These files would be downloaded and saved in an external scripts directory that can be archived. The test itself would not have pass/fail per se, but would be used to download these files so they can be scanned as part of a subsequent dependency scan. Local files are skipped since they should already be included in the codebase and scanned.

The benefit of doing this as a browser-based test is it only downloading what's ultimately sent to the browser, and eliminates the need to scan various different file types, how to managed scripts injected by code, etc.