core, db: Adding Cpu Qos DB config

Adding the Cpu Qos db config,
the Cpu Qos consists of one parameter: cpu_limit.
The parameter will be added to the qos table.
support for this feature is for all 3.x versions.

Also changed Storage Qos insert and update stored proc to fit common
behavior ("insert"+"storage"/"cpu"+"qos").

Change-Id: I533bcc601ac44289c51f5d56a6da0dd2455116d6
Bug-Url: https://bugzilla.redhat.com/1084930
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>