Integrate with async_hooks

[aleclarson]

By taking advantage of the async_hooks API, users of jumpgen would be able to import the API from jumpgen/async_hooks instead of destructuring or passing around the context object within the generator.

There are two benefits I see to using async_hooks (more specifically, AsyncLocalStorage).

1. Import auto-completion in IDEs
2. Allow functions declared outside the generator to use jumpgen APIs, without having to pass it as an explicit argument