Deno and Browser support

[iacore]

Currently, JS code generated by Ditto include each other with import 'package_name/...'.

• need special package.json set up
• need bundler like Vite to be used in browser

If possible, it might be better to use relative import everywhere. This will allow the generated code to be used in browsers directly with a dumb HTTP server.

Alternatively, generating a import maps for Deno should be easy, without any modification to JS generated. We need to also specify npm dependency as npm:xxx, and Deno stub for node modules in the import map.

Also, import map in browser is getting supported: https://caniuse.com/import-maps

Important: About trailing slash in import map: https://github.com/WICG/import-maps#packages-via-trailing-slashes