Verify list_instance_action attributes of Nova API

This patch adds the JSON schema for Nova V2 & V3 list_instance_actions
API response and validate the response with added JSON schema
to block the backward incompatibility change in the future.

The response body of list_instance_actions V2 API is below:

{
    "instanceActions": [
        {
            "action": "reboot",
            "instance_uuid": "b48316c5-71e8-45e4-9884-6c78055b9b13",
            "request_id": "req-3293a3f1-b44c-4609-b8d2-d81b105636b8",
            "user_id": "789",
            "project_id": "147",
            "start_time": "2012-12-05 00:00:00.000000",
            "message": ""
        }
    ]
}

The response body of list_instance_actions V3 API is below:

{
    "server_actions": [
        {
            "action": "reboot",
            "server_uuid": "b48316c5-71e8-45e4-9884-6c78055b9b13",
            "request_id": "req-3293a3f1-b44c-4609-b8d2-d81b105636b8",
            "user_id": "789",
            "project_id": "147",
            "start_time": "2012-12-05T00:00:00.000000",
            "message": ""
        }
    ]
}

Partially implements blueprint nova-api-attribute-test

Change-Id: I81a21a4ec0522318fd20c3db3e534fdcea7b8715
Merge "Verify list_instance_action attributes of Nova API"