dealing with environment variables

[edublancas]

There are a few environment variables that we should log to understand where are users running our code. For example, we want to know if they're running on Binder to know usage; but we should not count this in the retention graph since these are one-time sessions.

• readthedocs: this does not give any useful info so we should ignore events - this is already implemented
• GitHub actions: we're currently disabling telemetry if running on GitHub Actions, instead, we should log it but do not count it in the retention graph as they are one-time sessions
• Binder: we should log but not count them in the retention graph
• Sagemaker: log it but do not count in the retention graph as they'll look as different users if they reset the image