Improve/extend CLI prompt tools

[rpreen]

As of 1.2.0 the CLI prompt tools were added:

• $ aisdc gen-attack tool that produces the attack config attack.yaml for running attacks on the CLI
• $ aisdc gen-target tool that produces the directory target_dir/ that contains a target.yaml and model/data files for running attacks on the CLI
• subsequently running $ aisdc run target_dir/ attack.yaml executes the attacks and generates a report

These tools need to be improved and extended to provide a better user experience, such as more graceful exiting, and support for different scenarios when the model was not trained in Python, and where the data may be large and not able to be copied and also to handle various preprocessing situations. It seems likely that the aisdc/attacks/target.py will also need to be modified and an aisdc/attacks/model.py may need to be created to wrap target models to encapsulate non-scikit-learn models with fit(), predict() etc. functions that the attacks can assume exists.