Generate a setup.py file for downloaded python extensions

[radu-stefan-dt]

Summary
Packaged python extensions don't contain the setup.py file required for re-building them. This breaks the flow where user downloads a python extension, makes a change, and wants to package and upload it.

Current vs. Expected Behavior
Currently, when a downloaded python extension is built, the command errors with message message:

"ERROR: Directory '.' is not installable. Neither 'setup.py' nor 'pyproject.toml' found."

Ideally, after downloading the extension, during the unpacking process we would generate a setup.py file. At minimum level with just the sdk reference and a message for the user to add remaining dependencies, but ideally we'd detect and list them all there so there's no need for further action.