Allow pact-stub-server to respond data that depends on request

[canny]

Let's make pact-stub-server smarter by allow it to refer request data to be a part of response data like attached picture below. Furthermore, it would be really nice if it can refer to value in API path as well. xD

https://pact.canny.io/admin/board/feature-requests/p/allow-pact-stub-server-to-respond-data-that-depends-on-request

[canny]

This issue has been linked to a Canny post: Allow pact-stub-server to respond data that depends on request 🎉