[APM-CI][Python] Improve Jenkins builds to support `python nightly`

There is no `nightly` docker image available at [python docker images](https://hub.docker.com/_/python/). Investigate if there are other docker repositories offering python nightly builds, and add to Jenkins test handling if available.

Start by reviewing the Python Docker images linked in the issue and researching other repositories that publish Python nightly builds. Then inspect the Jenkins test handling to determine where a nightly image would be configured. Done means a viable nightly image source is identified and Jenkins can run the relevant tests against it.

Written by the indexing model from the issue text.