Need "step 0: get Python and Hatch" on https://www.pyopensci.org/python-package-guide/tutorials/get-to-know-hatch.html

[zackw]

People who aren't real familiar with what already comes with the OS, and what comes with core Python, may get stuck in step one of https://www.pyopensci.org/python-package-guide/tutorials/get-to-know-hatch.html when the recommended "pipx install hatch" command throws a "no such command pipx" error message.

Those instructions should come with a leader reminding people that they need to have Python installed in the first place, and then that Hatch is not part of core Python and needs to be installed itself. As discussed face-to-face in the sprint, it may make sense to drop pipx entirely and just recommend "pip install hatch" for naive users.

(Related to #265)