[Scenario]: Demonstrate Calling of an Azure Function for External Functionality

### Describe the scenario

Add a flow where an Azure Function is called to provide functionality that is available only externally before proceeding with the API Management backend API call.

### Improvement to Project

API Management has a curated set of libraries that can be used. Sometimes, a call to an external function may be required to augment functionality that API Management cannot provide natively. Often times, such calls are made prior to calling the backend API. Showing this approach is very useful to many customers as this is a common scenario with which we have worked.

### Are you able to collaborate and/or submit a pull request?

Yes