apparmor: Improve debug print infrastructure

apparmor: Improve debug print infrastructure

Make it so apparmor debug output can be controlled by class flags
as well as the debug flag on labels. This provides much finer
control at what is being output so apparmor doesn't flood the
logs with information that is not needed, making it hard to find
what is important.

Signed-off-by: John Johansen <john.johansen@canonical.com>