Added support for queries that return scalar results

[jasonf20]

Queries such as SHOW CREATE JOB <job_name> return scalar results. A scalar result is returned as:

[
    {
        "status": "Success",
        "kind": "upsolver_scalar_query_response",
        "result":
        {
            "scalar":
            {
                "value": "<value_here>",
                "valueType": "<value_type_here>"
            }
        }
    }
]

This commit transforms this result into a 1x1 grid with a column name of
valueType.

Need to amend

[navado]

Can you please add example of this query to examples and test case to DB API tests?

[jasonf20]

I didn’t see a way to add a test easily since the test_dbapi.py file doesn’t mock the entire response, it mocks just the grid, so that wouldn’t test anything. Since the change happens in the response parsing which I didn't see an existing spec for.
If there is a place to add this please let me know where.

I also don’t think it really is required in the example since it’s just another query from the user’s perspective. In addition there isn't a section about creating jobs right now so there also isn't a good place to add it to in the README.

[jasonf20]

Added an example how this would be used in the examples.py file