WIP: Add deb sources

As more and more repos will depend on correctly setting up the internal deb sources, it is probably a good idea to make this part of the default CI config templates.

Pushing this as a WIP to test it. Feedback is welcome, @jon.azpiazu.

scripts/add-deb-sources.bash

+#!/bin/bash
+
+apt-key adv --fetch-keys http://roboticsbuilder:8088/aptly_repo_signing.key
+echo "deb http://roboticsbuilder:8088/ tecnalia-test main"  > /etc/apt/sources.list.d/tecnalia.list
+apt-get update
+
+echo "yaml https://git.code.tecnalia.com/tecnalia_robotics-public/gitlab_templates/raw/master/rosdistro/rosdep_tecnalia.yaml" >> /etc/ros/rosdep/sources.list.d/20-default.list
+rosdep update