Verify list_addresses_by_network APIs attributes

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

The response body of server list_addresses_by_network V2 API is below:

{
    "private": [
        {
            "version": 4,
            "addr": "192.168.0.3"
        }
    ]
}

The response body of server list_addresses_by_network V3 API is below:

{
    "private": [
        {
            "version": 4,
            "addr": "192.168.0.3",
            "type": "fixed",
            "mac_addr": "aa:bb:cc:dd:ee:ff"
        }
    ]
}

Partially implements blueprint nova-api-attribute-test

Change-Id: I76e25523708fb9454518f215dc60f201d7483464
Share Certificates API's tests between V2 & V3

There is a lot of copy&paste test code for Nova v2/v3 API tests.
In addition, we need to add many checks for API test coverage.
As the result, we should apply the same changes to v2 and v3 tests.

This patch reuse the test code of V2 and V3 Certificates APIs
Inheriting the V2 Certificates API's test from V3 tests.
Also removing the status code check which is different between
V2 & V3. Status code has been validated at client side.

Partially implements blueprint nova-api-test-inheritance

Change-Id: I98e03cecdbd36e521d007bbfb92a5f9818ff28f6
Merge "Share Certificates API's tests between V2 & V3"
Merge "Verify list_addresses_by_network APIs attributes"