Create tests for SR-IOV feature (networking)

We need to add tests for Fuel which will cover use cases of new SR-IOV feature for networking. New tests cases should be added to the manual release acceptance tests suite on baremetal, because the feature can't be used on virtual environments like QEMU or Virtualbox. They will be automated as soon as baremetal driver for fuel-devops is implemented and fuel-qa support is added for it.

Also OSTF tests must be aligned with the feature if necessary (e.g. instance live migration, security group creation and so on).

Base test scenario for new cases is the following:

1. Create new environment with VLAN segmentation for Neutron
2. Add nodes which support SR-IOV (e.g. 3 controller and 3 compute+[ceph/cinder ] nodes)
3. Check that SR-IOV support is correctly detected by nodes discovery system (Nailgun agent)
4. Enable SR-IOV for some interfaces (w/o networks assignments) on compute nodes.
5. Run network verification
6. Deploy environment
5. Run network verification
6. Run OSTF
7. Create instance connected to SR-IOV port
8. Assign floating IP to it
9. Check that instance is reachable via floating IP

Negative test cases are also need to be implemented:

 * SR-IOV can't be used with tunneling segmentation (GRE/VXLAN)
 * SR-IOV can't be enabled on interfaces which do not support this technology (agent reports that sriov is not available for NIC, corresponding button on UI is not shown)
 * networks (including Private) can't be assigned to interface with enabled SR-IOV
 * SR-IOV can't be enabled if DPDK usage is activated (actual behaviour is not clear from specification, so this point will be clarified)
 * SR-IOV can't be enabled on non-compute nodes (actual behaviour is not clear from specification, so this point will be clarified)