Bigbank sample should use wires instead of hacked up SOAP addresses

The bigbank sample uses a hacked up / fixed SOAP address in the WSDL to connect the external service in the webclient module component to the entry point of the account module component.

This is not how it should work. One very important feature of SCA illustrated by BigBank is to allow module components to be wired together. So we should change the sample to use wires. This is how the sample is actually described in the "Building your first SCA application" spec companion document.