moving ALTQ out of contrib

[Gleb Smirnoff]

  Hi!

  With the new ifnet KPI, that is now being developed in projects/ifnet,
the ALTQ will need some tweaking. It is discontinued by initial author
for a decade now, and it has already experienced direct commits in
our tree. Thus, I see no good reasons to continue keeping it in contrib.

In NetBSD they have it in sys/altq.

I'd prefer to move it to sys/net/altq.

Any objections or better ideas?

-- 
Totus tuus, Glebius.