feat(ui): add js/css mappings

[fiftin]

Description of the Change

Enables debugging of JavaScript in the browser.

How to test the Change

• npm build
• enable the plugin
• open browser's devtool

Changelog Entry

Added - configuration option to webpack

Credits

Props @fiftin

Checklist:

• [x] I agree to follow this project's Code of Conduct.
• [x] I have updated the documentation accordingly.
• [x] I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• [x] All new and existing tests pass.