db, core: aggregate qos and storage qos impl

- DB and DAL changes: create qos table to accomodate qos objects and include
storage qos and its limits.
- added qos_sp.sql to add default sp.
For more information see: http://www.ovirt.org/Features/aggregate_QoS,
http://www.ovirt.org/Features/blkio-support

Change-Id: I1a9af59277b5055453159f002f19046c0051d63b
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>