[pkg-apparmor] Bug#870697: Please provide systemd service file which doesn't require the SysV init script

[intrigeri]

intrigeri:
> On https://salsa.debian.org/apparmor-team/apparmor/merge_requests/6
> I've discussed with Jamie how to more fully align with upstream, which
> is required to fix this bug. See the "resolved" discussions there.

… more specifically the discussion that starts there:
https://salsa.debian.org/apparmor-team/apparmor/merge_requests/6#note_29153