azdev extension/cli create -- additional functionality

So this is a proposal to add new parameters to the command:

**--autorest-input-file (json or md file within locally cloned azure-rest-api-specs)**

If the parameter is added, **azdev** would run following docker command:

docker run -ti -v **azure-rest-api-specs-folder**:/azure-rest-api-specs -v **output-folder**:/generated zikalino/autorest.devops /azure-rest-api-specs/**path-to-md-file**.md **azdev**

The command will produce following files in **output-folder**:
- _client_factory.py
- _help.py
- _params.py
- commands.py
- custom.py
- report.md

These files can be used to replace scaffolded files with complete prototype implementation of command module.

Start at the azdev extension/cli create command entry point and inspect how it handles command parameters. Verify the proposed --autorest-input-file behavior against the documented Docker invocation and output files: _client_factory.py, _help.py, _params.py, commands.py, custom.py, and report.md. Done means the command accepts the input path and produces the listed prototype files in the output folder.

Scritto dal modello di indicizzazione a partire dal testo della issue.