Feature of Health check for postgres

[siddhureddy5372]

Proposal

Use case. Why is this important?

When using postgres_exporter in Docker containers, having a health check endpoint similar to /metrics is beneficial because it simplifies configuration. Instead of setting up another HTTP server or exposing an extra port, a single endpoint for health checks ensures efficient resource use and easier management. This approach is particularly useful in microservices architecture, where streamlined monitoring and integration with other services are crucial.
“Nice to have” is not a good use case. :)

[jcjones]

See also #615, which this is at least somewhat a duplicate of.