Watch metrics for expected positive results
Description
Prometheus is great for watching a variety of metrics types. We already plan on alerting on negative indications, but we should also consider watching for positive results, such as an increase in click-through rate, or utilization of a feature. By tying an issue to a desired metric, and optionally setting a desired threshold or percent increase, we could measure and indicate if the feature was successful, alert on failures, and possibly block incrementing the rollout, or even automatically turning off feature flags.