Improve local developer vscode debug experience

[xinyi-joffre]

It would be great to have a .vscode launch.json file that can be used to start a debugging session for running the ml_service scripts, or more importantly, for running the scripts inside the code folder (the pipeline steps).

Desired experience: A new user of the repo should be able to open up the repository in vscode, go to the debug tab, and then see a dropdown of scripts to debug.