Create test transcript middleware for Python

[gabog]

Implementation for microsoft/botframework-sdk#5341

[dciborow]

This is what I put together....

https://github.com/dciborow/botbuilder-python/blob/master/samples/tests/adapter.py
https://github.com/dciborow/botbuilder-python/blob/master/samples/tests/test_bot.py

[congysu]

iiuc, this is part of #341 .

[axelsrz]

Per conversation with @congysu this was resolved in #341