Expose job resource in batch API

[illusional]

It's useful for us to be able to programmatically access the resource data from a job and batches.
This is stored as a dataframe, we'll send back as json with orient='split'.

I've tested this in a dev deploy, and worked fairly well.

In my own interest, here's how to convert it back into a dataframe:

import pandas as pd

response = {} # response from Hail Batch
dataframes = {
    key: pd.DataFrame(data=values['data'], columns=values['columns'])
    for key, values in response.items()
}

[EddieLF]

Love it

[illusional]

I have suggested this upstream, as it reduces the amount of conflicts we might receive, and might be useful for them: hail-is#14328

[jmarshall]

Couple of very minor comments, otherwise looks good!