Improve query audit log including user

Pinot currently supports query audit logging. I can check in controller or broker log files.
(example)
```
url string passed is : http://:7001/query/sql
Query: select avg(score) from transcript_sunny group by subject Time: 213
Handled request from POST http://:9001/sql, content-type application/json; charset=UTF-8 status code 200 OK
```

But it will be a good enhancement to log the user in query.
In production, I think it is important point.

cc. @kishoreg

Start by locating the query audit logging paths for the controller and broker, including handling for the /query/sql and /sql endpoints shown in the examples. Determine how the authenticated user is available at those points; done means audit entries include that user alongside the query and existing request details.

Written by the indexing model from the issue text.