Adds type definitions for typescript users

[southpolesteve]

Another option (IMO less desirable) would be to publish them to the @types organization. If that is preferred, just let me know!

[dcousens]

I think @types is preferred tbh, but, this is an ACK from me otherwise

[calvinmetcalf]

is there a away we could grab the version in from node somehow ?

[dcousens]

@calvinmetcalf wrong PR?

[calvinmetcalf]

no, the typings for node

[southpolesteve]

@calvinmetcalf not sure I 100% understand. That is what I am trying to do here. I could take it a step further and make this package dependant on @types/node