Extend span tracing for Python

[meiqimichelle]

Right now, the Buildkite Test Analytics Ruby test collector (our reference implementation) is the only Test Analytics collector that automatically captures and transmits span data. This Python collector can transmit information, but data capture must be done manually.

This issue is to record suggestions we've got from customers about how to extend the Python collector with a similar functionality to the Ruby one (see links to examples in the Tracing section of the README in this repo).

What would be fantastic is similar functionality in python as you have in the Ruby collector. Django's ORM offers a similar hook point - https://docs.djangoproject.com/en/4.1/topics/db/instrumentation/ - as ActiveRecord (I'm sure there's something similar for SQLAlchemy) and there are a few libraries that cover how folks do HTTP calls in Python. Between urllib, requests, and httpx you'd cover like 90% of the usecases.

Further notes or pull requests welcome.