Port our ISO build system to Jessie

It’s unclear whether the Vagrant one can/will be ported, or if we’ll instead focus on migrating to Docker. This shall perhaps not block migrating the manual build instructions and Puppet module to Jessie.

Feature Branch: feature/9262-build-on-jessie, puppet-tails:feature/9262-build-on-jessie

Attachments

• diffoscope-wheezy_to_jessie-no-timestamps.html.xz

Related issues

• Blocked by #9523 (closed)
• Blocks #10592 (closed)
• Blocks #11006 (closed)

Original created by @intrigeri on 9262 (Redmine)