feat: support offline access via self-contained maidr.js

Currently, we are using maidr.js@latest via cdn. While keeping this approach, address the following:

- [ ] ci: bundle the latest `maidr.js` each time we release `py_maidr`

- [ ] feat(options): allow users to choose `self-contained` option within maidr.show() for offline access

- [ ] feat: automatically fall back to the bundled `maidr.js` in the case where Internet connection is unavailable