add autopkgtest support to Fuego

[daniel.sangorrin@toshiba.co.jp (Daniel Sangorrin)]

Hi Tim,

I send you a patch that enables executing and parsing the results of 
autopkgtest from Fuego.

[PATCH] autopkgtest: add support for debian package tests

Honestly, I wrote it in a few hours so it might need more testing.
So far it seems to work fine on the beaglebone (Debian 9.2 armhf)
for the tests in the packages libzerg, libproxy, fakesleep (randomly
chosen from https://ci.debian.net). Also please read the commit
message to understand the consequences of running the test (it
installs a testbed, so you need a reproducible deploy system).

To Debian QA/Autopkgtest developers: I'm not an expert on autopkgtest, 
if you have any comment please let me know.

Best regards,
Daniel