Make a /metrics handle at the snowflake broker for the stats collector
We have metrics being written to a log file for now as specified in #21315 (moved), and the metrics team is working on setting up a collector module for it in #29461 (moved). We should add a handler at the broker at snowflake-broker@bamsoftware.com/metrics
so the collector can make GET requests for the collected metrics.
The response should be
Content-Type: text/plain; charset=utf-8