Sprint 1: Service can proxy requests to a mock broker

In order to deploy the billing service in between CAPI and our brokers, we want the service to be able to proxy OSBAPI requests to downstream brokers. This ticket is scoped to the Go code for proxying. Changing how we deploy our brokers to accommodate this is out of scope.

Acceptance Criteria

• With multiple mock brokers running, one or more Go http tests can send requests to the server and they will be proxied to the correct mock broker.

---

Security considerations

This first pass will not handle OSBAPI authentication.