core: Cluster parameters override - scheduler \ actions \ queries

This feature allows to configure the 'emulated machine' and 'cpu model'
parameters for each VM separately instead of relying on the cluster default.

Bug-Url: https://bugzilla.redhat.com/838487
Feature-page: http://www.ovirt.org/Features/Cluster_parameters_override
Change-Id: Iea8117d8416c74b381aa8475c3fc8b02a344dbfb
Signed-off-by: Eldan Shachar <eshachar@redhat.com>