Add features to config.py

[logandhillon]

Make config.py set up Python env

Should download requirements.txt from main, then prompt the user to either install requirements to main Python env., or create a venv.

This should happen before the imports

[logandhillon]

Also, create shell script:

Should launch: Python (sys.executable [absolute path to bdsh.py])

On Windows

Create bdsh.bat, don't forget to @ the line

On UNIX

Create bdsh binary executable