Add unzip.py script to repository

On Parabola Linux the `unzip` package is not available due to the fact
that it is not libre enough. The `busybox unzip` program does not unzip
several different zip versions. Luckily `python` has all of the zipfile
tools needed to at least match the functionality of the `busybox unzip`
binary. This commit adds a python script to work with zip files (`unzip`
only because who would ever use `zip` to archive files on Linux?!).