Expose the Kafka topic ingestion offset via a specific API

When ingesting new events from a Kafka topic, there isnt an easy way for users to know the high watermark of ingestion. There is a debug API that exposes the offset along with a lot of other info. It may be better to expose the offset through a specific API.

Start by locating the existing debug API and the Kafka topic ingestion path described in the issue, then determine how the ingestion high watermark is represented. Done means users can retrieve the ingestion offset through a specific API without relying on the broader debug response.

Written by the indexing model from the issue text.