Install the wheel package into the dev image

For building Python packages that contain wheels, the wheel package must be installed. Because wheel is not listed as a direct dependency of a package that requires it, it must be present in the system before attempting a build. It isn't always required, but I don't know if there is a way of determining that just by looking at a Python package ¯_(ツ)_/¯

We didn't notice this in our other mirror because it differs from vanilla in that some additional packages are installed as part of producing the NID images.