docs: Update python.md to include Location import

[jordan-gillard]

This PR updates the Python example code to include Location in the import from amadeus. The code was broken without this import.

It also removes the virtualenv package dependency in favor of the Python standard libraries venv module (introduced in Python version 3.3). No one really uses virtualenv anymore unless they have a project that requires multiple arbitrarily-installed Python interpreter versions.

[tsolakoua]

Thanks a lot for your contribution :)

[jordan-gillard]

Thanks a lot for your contribution :)

More to come!