Improve error handling in controller

[gortiz]

This PR is trying to fix the two first controller errors listed in #14950:

• On errors, Pinot controller query endpoints inconsistently return broker-like JSON error payloads (if the error is detected by the broker) or plain text (if the controller itself detected the error)
• The Pinot controller detected errors that were not logged.

It also optimizes the way controllers pipeline query results from brokers. The current version should be faster (see https://schoeffm.github.io/posts/response-streaming-between-jaxrs-and-webcomponents-part1/) and, most importantly, zero-copy (while previous code copied the query response on the heap not once but twice!!!)