Better error logging in batches

This is more a feature request than issue report:

_As operations monitoring the Lambda-based ETL process, I'd like the failed batches that are stored in DynamoDb to include more diagnostic information._

We had some loading errors in a newly set up table, and the information available in the batches are just:

```
{
"xxxx.redshift.amazonaws.com": {
"error": {
"code": "0A000",
"file": "/home/awsrsqa/padb/src/pg/src/backend/commands/commands_copy.c",
"length": 138,
"line": "2168",
"name": "error",
"routine": "DoCopy",
"severity": "ERROR"
},
"status": -1
}
}
```

We did manage to eventually find the corresponding log stream and diagnose it further, which was caused by a wrong copy command (which I suspect is yet another issue on its own), and quite a lot of more detailed error logs were actually available.

So here I wonder, would it be possible to include more details in the failed batches, so we can easily query it with just 'queryBatches.js'?