Hyper-V VLAN Trunks support

Neutron trunk ports have been introduced in newton [1], and they can be used to setup a VLAN trunk.

In order to set a given Hyper-V vSwitch port to VLAN trunk mode, the Msvm_EthernetSwitchPortVlanSettingData objects [2] will have to have the following fields set as follows:

- NativeVlanId - with the given Neutron port's segmentation_id / vlan_id.
- TrunkVlanIdArray - with the given Neutron trunk port's subports segmentation_ids / vlan_ids.
- OperationMode - 2 (Trunk Mode).

The following things will have to taken into account:

- TrunkVlanIdArray should not be set if the given OperationMode is Access, it will have to raise an Exception.
- if the OperationMode is Trunk Mode, the NativeVlanId field must be set.

[1] https://wiki.openstack.org/wiki/Neutron/TrunkPort
[2] https://msdn.microsoft.com/en-us/library/hh850151(v=vs.85).aspx