devel branch FTBFS since apparmor/2.11.0-3+deb9u2 reached stretch-proposed-updates

This will affect Tails 3.6 due to #15341 (closed).

Feature Branch: feature/15341-stretch-9.4

Original created by @intrigeri on 15372 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information