[pkg-apparmor] Bug#981442: Bug#981442: apparmor: Please do not install by default or depend on python3

[intrigeri]

intrigeri (2021-02-01):
>> or avoid making it hardly depend on python3?
>
> I did not check how hard that would be yet. If this is a post-Buster
> regression, I'll do my best to look into it shortly!

The only reason why apparmor "Depends: python3" in current testing/sid
is that /usr/sbin/aa-status is written in Python. 

Upstream commit 8f9046b1b179190d0003ae1beacf460ee93c5090, included in
upstream 3.0.0 release, and thus in Debian experimental already,
ported that program to C, which should allow dropping the dependency
on python3. I did not check how hard it would be to backport
this commit.

There's some more context in
https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/1865519