This hijacks some old crufty log machinery to enable log streaming from
the new Deployments V3. This exposes two new methods, one generator and
one that just dumps a buttload of logs in your lap.

By way of example:
```
>>> from gradient import gradient_deployments
>>> import json
>>>
>>>
>>> logs = gradient_deployments.get_deployment_logs(
...     deployment_id='6753a6cc-393a-478d-bc29-9e8828a0aa2f',
...     limit=5,
...     api_key='<REDACTED>')
>>> print(json.dumps(logs, indent=4))
[
    [
        2,
        "",
        "2021-12-13T21:41:39.711Z"
    ],
    [
        3,
        "  Welcome to Streamlit. Check out our demo in your browser.",
        "2021-12-13T21:41:39.711Z"
    ],
    [
        4,
        "",
        "2021-12-13T21:41:39.711Z"
    ],
    [
        5,
        "  Network URL: http://10.42.40.230:8501",
        "2021-12-13T21:41:39.711Z"
    ],
    [
        6,
        "  External URL: http://172.83.13.4:8501",
        "2021-12-13T21:41:39.711Z"
    ]
]
>>>
>>> logs = gradient_deployments.yield_deployment_logs(
...     deployment_id='6753a6cc-393a-478d-bc29-9e8828a0aa2f',
...     limit=5,
...     api_key='<REDACTED>')
>>> next(logs)
LogRow(line=2, message='', timestamp='2021-12-13T21:41:39.711Z')
```