Verify list_virtual_interfaces attributes of API

This patch adds the JSON schema for Nova V2 list_virtual_interfaces
API response and validate the response with added JSON schema
to block the backward incompatibility change in the future.

This patch also adds the mac address in common parameter type for
reusability amongs other schema.

The response body of list_virtual_interfaces V2 APIs is below:
{
    "virtual_interfaces": [
        {
            "id": "%(id)s",
            "mac_address": "%(mac_addr)s",
            "OS-EXT-VIF-NET:net_id": "%(id)s"
        }
    ]
}

Partially implements blueprint nova-api-attribute-test

Change-Id: I261917920aea880cf3419f23478b6df322a10ded
Merge "Verify list_virtual_interfaces attributes of API"