Instead of waiting a long time, let's just check that networking truly
is disabled, in the same way we do for the MAC spoofing tests -- after
all the code for the "Diable networking" feature actually originates
from the MAC spoofing feature. This way we do not have to introduce a
static wait for 120 seconds, and we do not need the anti-test.

Fix-committed: #10945

Fix-committed: #10943

Fix-committed: #10939

Fix-committed: #10893

refs: #10943

It feels more maintainable to use a standalone file, than to patch an existing
one in /etc.

refs: #10943

Disable IPv6 for the default wired connection, so that NetworkManager does not spam the logs with IPv6 router solicitation failure.

Note that this does not fix the problem for other connections.

Refs: #10939

Conflicts:
	wiki/src/doc/first_steps/introduction_to_gnome_and_the_tails_desktop/nautilus.png

AppArmor regexps don't understand '+' yet, so
/usr/lib/cups/backend/ipp14 was not matched.

Will-fix: #10893