Add DebianPkgs module.

# Fathead Pull Request


**What does your instant answer do?**
Returns the version and short description of a Debian package in the current stable and testing repositories.


**What problem does your instant answer solve (Why is it better than organic links)?**
It provides enough information at a glance to tell a user the generalities of a package and the current versions in Debian. Organic links rarely provide such information without navigating to the destination.


**What is the data source for your instant answer? (Provide a link if possible)**
https://packages.debian.org/stable/allpackages?format=txt.gz
https://packages.debian.org/testing/allpackages?format=txt.gz


**Why did you choose this data source?**
This is the authoritative list of packages in Debian


**Are there any other alternative (better) data sources?**
There are alternatives, but they are not likely to be better than the list from packages.debian.org.


**What are some example queries that trigger this instant answer?**

    debian vim
    debian package plink
    netcat debian pkg


**Which communities will this instant answer be especially useful for? (gamers, book lovers, etc)**
Debian users; possibly Ubuntu users


**Is this instant answer connected to a DuckDuckHack [instant answer idea](https://duck.co/ideas)?**
https://duck.co/ideas/idea/277/debian-and-derivatives-like-ubuntu-package-infor


**Which existing instant answers will this one supercede/overlap with?**
None known. There is a unmerged branch at https://github.com/duckduckgo/zeroclickinfo-fathead/tree/debian_pkgs, but it hasn't been touched in years.


**Are you having any problems? Do you need our help with anything?**
None.