Extend the Aries Agent Test Harness AFJ Backchannel to support more tests

[swcurran]

Background: The Aries Agent Test Harness (AATH) contains a large number of Aries interop in the form of Behaviour Driven Development tests created based on the Aries RFCs. The AATH Aries Framework JavaScript Backchannel is an implementation of an Aries Controller for an Aries Framework JavaScript instance that:

• takes requests from the Aries Test Harness to perform test steps, and calls the Aries Framework JavaScript instance to carry out the steps, and
• reports back to the Aries Test Harness on the activities of the Aries Framework JavaScript instance in completing the tests steps

Currently, the AJF Backchannel only supports some of the steps in the tests, because the controller has been written to only understand and respond to some of the requests from the Aries Agent Test Harness.

This task is to review the tests in the Aries Agent Test Harness repository and figure out which ones are testing capabilities supported by Aries Framework JavaScript today, and to then extend the Aries Framework JavaScript Backchannel to handle the steps implemented in those tests. Since the core of the Aries Framework JavaScript Backchannel is in place, this task is adding more instances of handling requests and invoking Aries Framework JavaScript to implement the request.