Add type definitions

This is just an issue to track interest in type definitions for the framework.

If there is enough interest I will consider working on adding definitions as I have time. With the consent of the maintainers, this can be directly in the repo or if a separation is more desirable they can just be added to the Definitely Typed library.

https://github.com/DefinitelyTyped/DefinitelyTyped

Please let me know if this interests you by giving the thumbs up here.

I would also love some feedback from @mikermcneil

The issue names no repository files, tests, or entry point; begin by reviewing the Sails framework API and the linked DefinitelyTyped project. Done would require an agreed scope and a complete set of type definitions, but the issue does not specify either.

Written by the indexing model from the issue text.