Simplifications: make apt_conf_snippet repeat less code, make code that
generates sources.list more concise.
Remove all inline content in favor of templates and static files.
The ability to include sources for static files was needed for
the main 'preferences' file, so it was added to the preferences_snippet
define.
Signed-off-by: Gabriel Filion <lelutin@gmail.com>
With the new define, it's easy to add an apt.conf snippet in apt.conf.d
It accepts either 'sources' to get a static file or 'content' to define
content inline or with the help of a template.
Put it to use where we create files in apt.conf.d
Finally, fix the dependancy to the apt_config file (however, I don't see
the need for this dependancy)
Signed-off-by: Gabriel Filion <lelutin@gmail.com>
