All information which are need for those operations is already stored in
the cookie.
We decided not to bump libnv version because this API is not used yet in the
base system.
Reviewed by: pjd
cnv API is a set of functions for managing name/value pairs by cookie.
The cookie can be obtained by nvlist_next(), nvlist_get_parent() or
nvlist_get_pararr() function. This patch also includes unit tests.
Submitted by: Adam Starak <starak.adam@gmail.com>