Feature: Browser-compatible specifier resolution

[GeoffreyBooth]

I can create a package that imports dependencies and works natively on the web, without needing a build step.

Modules from NPM can be used in my package, without requiring any transpilation or transformation. Tools such as IDEs and linters can understand these dependencies, and all agree on what a specifier means.

Use cases 22, 28, 29.

[ljharb]

I believe package name maps in the browser will make this possible; very much like #107 (comment)