Terminal debug experience in Python Debbuger Extension #1612

We are implemented a debug terminal with shell integration, in order to do that we will need an extra implementation in debugpy side.

In order to start debugging from the terminal, we need to specify a connect or listen port in the command: python -m debugpy --connect 5678 file.py.

What we want is to be able to use only: python -m debugpy file.py and debugpy set internally the connect port by default to 5678.