core: Add vnic profiles to DB and entities

1. Add VNIC Profiles to the DB and create the business entities.
2. Handling upgrade scenarios.
3. Removing roles required also some handling in backend commands.

See also: http://wiki.ovirt.org/Features/Design/Network_QoS and
http://www.ovirt.org/Features/Vnic_Profiles

Signed-off-by: Ofri Masad <omasad@redhat.com>
Signed-off-by: Oved Ourfali <oourfali@redhat.com>
Change-Id: Id0525a6d30995fe896499fed283638b93cae5e41
Signed-off-by: Alona Kaplan <alkaplan@redhat.com>