Convert to TS or supply ambient definitions

[chriskrycho]

As part of Ember.js RFC #0800, this package needs to supply type definitions. Preferably, this would happen by converting to TS and generating from the source; as an alternative, it can publish ambient types (presumably starting with the ones on DefinitelyTyped).

All the members of the Typed Ember team are happy to advise on how to do this; feel free to reach out in #dev-typescript on Discord if you have questions!

[locks]

Katie, Kelly and I briefly discussed this during the weekly CLI call and the general opinion is that people with more context of the implications and current active contributors should drive the decision.
@rwjblue @ef4 @bertdeblock what do you think is the best plan going forward?

[ef4]

We have the start of types here because Embroider needed them. They weren't intended to be complete, just enough API to do what Embroider needed to do.

[gitKrystan]

I did a quick spike on what actual TS conversion would take, and it looks like it would be quite a project because many of the libraries this project replies on do not themselves have types. Ambient definitions would be way easier. I might spike on that later this week starting with @ef4's types and adding types only for the API documented at https://ember-cli.com/api/.