Add typescript support

[wweaver]

Is your feature request related to a problem? Please describe
I'm trying to use this project in my typescript project and I'm having to build the typescript functionality I need.

Describe the solution you'd like
Either update the project to add support or add an ancillary project that provides @types/sfmc-fuelsdk-node

Describe alternatives you've considered
I've tried to build this myself for my needs but I don't know the code that well, nor do I know node all that well to do it correctly.

Additional context
I started doing this and it's in the very early stages. Would be nice if this was done by someone that knows the code.

[eyesurewould]

Yes please!!