Update Python docs to include Python environments extension

[cwebster-99]

We are currently rolling out the Python Environments extension (100% of pre-release users) and soon to be for Stable users. We will need to update our docs library to include information about the extension and its features.

[cwebster-99]

Below is a list of docs sections that will need to be updated:

• https://code.visualstudio.com/docs/python/python-tutorial#_create-a-virtual-environment
• https://code.visualstudio.com/docs/python/python-tutorial#_install-and-use-packages
• https://code.visualstudio.com/docs/python/python-quick-start#_how-to-create-and-open-a-python-project-or-file
  • this could mention Create Project
• https://code.visualstudio.com/docs/python/python-quick-start#_ui-tour
  • update to include call out to Python Environments in the Activity Bar
• https://code.visualstudio.com/docs/python/environments
• https://code.visualstudio.com/docs/python/settings-reference