Add AppArmor profile to contrib

Add AppArmor profile to contrib. It's useful for greater lockdown than currently done by the binary.

It's rather generous on file and library access since cjdns drops the file limit to 0 by default, but it still won't let cjdroute access things it has no business with, like /home, /bin or random stuff in /tmp, even if that limit is somehow circumvented or setting the file limit to 0 is disabled.