Prometheus metrics for individual credentials

[CharlieC3]

I don't believe this is possible today without some kludging, but it would be great if we can get prometheus metrics on credential usage similar to how we can get metrics on Consumer usage with the Prometheus plugin.

In order to do this today, you'd need to create a new Kong Consumer for every credential as the Prometheus plugin can be configured to generate consumer-level metrics:
https://docs.konghq.com/hub/kong-inc/prometheus/configuration/#config-per_consumer

This becomes cumbersome at scale, especially when you want to create Consumers with many credentials.