Add API(v2) to update openrc

Add API(v2)  to update openrc

JIRA: YARDSTICK-720

API: /api/v2/yardstick/environments/openrcs/action
METHOD: POST
PARAMS:
{
    'action': 'update_openrc',
        'args': {
            'openrc': {
                "EXTERNAL_NETWORK": "ext-net",
                "OS_AUTH_URL": "http://192.168.23.51:5000/v3",
                "OS_IDENTITY_API_VERSION": "3",
                "OS_IMAGE_API_VERSION": "2",
                "OS_PASSWORD": "console",
                "OS_PROJECT_DOMAIN_NAME": "default",
                "OS_PROJECT_NAME": "admin",
                "OS_TENANT_NAME": "admin",
                "OS_USERNAME": "admin",
                "OS_USER_DOMAIN_NAME": "default"
            },
            'environment_id': environment_id
        }
}

Change-Id: Ie9a1614190a01456fd0896f0bdfd05f9d0724fc6
Signed-off-by: chenjiankun <chenjiankun1@huawei.com>