Add JS module detection rewriting

[tw4l]

Description

This PR modifies pywb to detect and rewrite JS modules. Global overrides are imported in modules via a new _wb_module_decl.js static file.

This also bumps wombat to 3.4.2.

Motivation and Context

JavaScript modules were previously not detected, which caused errors in replay for sites that use them.

Types of changes

• Replay fix (fixes a replay specific issue)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added or updated tests to cover my changes.
• All new and existing tests passed.

[ato]

I tested this on a site we've been handling trouble with (https://www.aucyberexplorer.com.au/). Unfortunately this site uses JavaScript modules that don't start with import or export so the is_module check doesn't trigger. It looks like wabac.js handles this problem by introducing a new esm_ modifier so the detection is based on the context in the referencing page rather than the contents of the script file alone.