Added virtual environment setup instructions in python.md

[JasonBalayev]

Included instructions for setting up a virtual environment in Python.

Tip within the page only goes over python packaging.

[learn-build-service-prod]

Learn Build status updates of commit 9d57cd2:

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OpenAPI/kiota/quickstarts/python.md	✅Succeeded

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[JasonBalayev]

@microsoft-github-policy-service agree

[JasonBalayev]

In my contribution, I forgot to include a reference to the official python docs on venvs -(https://docs.python.org/3/library/venv.html).

This may be helpful as a quick reference under any confusion.

[baywet]

Thanks for the contribution!