Avoid duplication and unnecessary installs between python base images and application images.
At the moment the various things are installed via apk and pip in both the Dockerfiles here and application that use them, possibly at different versions. I'm not sure how best to address this - my gut feeling is that each application should build directly from one of the official python images. But maybe there's something else.
This is potentially confusing, and might be a source of errors.
Also some Dockerfiles install stuff (like git and vim) which probably shouldn't end up in production images.