Stripe payments - WIP

Right now, just putting certain things in the backend.  The Access Token is for Developers (Gotten through OAuth).  The Customer Token is an id to identify a customer in Stripe (so, if we would like to 'save' a user's payment details, we will save their stripe customer id).  More details on shared customers [here]( https://stripe.com/docs/connect/shared-customers)

Will be going into navigator.game and I will add to this pull request.