Enabler: Add a /listing-information/status endpoint

[blairlearn]

The API should expose a /listing-information/status endpoint to report the health of the listing information lookup.

The endpoint should

• Call the Elasticsearch health check API for the listing-information index.
• If the Elasticsearch status is either green or yellow, return a status 200 and the text "alive".
• Otherwise, return a status 500 and the text "Service not healthy."

ESTIMATE TBD

Resources:

Prerequisites

Sub-Tasks

Notes

[blairlearn]

Combined with #58 to add a single /healthcheck/status endpoint