add more Python test templates

the Django one is nice, but it's really relevant only for larger webapp projects. it is not well adapted to more generic and smaller apps.

a normal and simple Python app would use the Python template here: it simply passes the build to setuptools which is responsible for running the test suite. we also build the binary installable by pip and provide it as an artefact, along with a local install that can be tested.

the Tox template does something similar but uses tox instead.

both builds use the latest Python image.