#270 js modules, resolve with nodeNext

[joepio]

• renames all imports to use .js
• adds linting rule to force this
• Note that this code has already been published at @tomic/react and @tomic/lib

PR Checklist:

• Link to related issues: closes Errors using @tomic/react in js project - Was not found in "module has no exports" type #270
• Add changelog entry linking to issue
• Add tests (if needed)
• (If new feature) added in description / readme

[joepio]

Tests passing locally