Document Open MCT public API using TypeScript type declaration files

[akhenry]

• Note that this issue is not about re-implementing the API using TypeScript

Summary

The Open MCT public API should be documented in such a way that commonly used IDEs can provide inline documentation and useful code suggestions. A reasonable way of doing this is using external TypeScript declaration files. A lot of our API is already implemented in jsdoc which could potentially be used for auto-generating typescript declarations.

Stages

1. Prototype by documenting one fairly simple API
2. If necessary, lint our existing JSDocs and correct any issues in order to smooth the auto-generation of typescript definitions for the rest of our API
3. ?
4. Profit!