Track Ecto query metrics globally (Custom metrics)

[matsimitsu]

Right now we track ecto query metrics as instrumentation (events).

It would be great if we could expose a dashboard with some global ecto query metrics (e.g. total query throughput / response time and perhaps queue/decode times? (#318)). This also gives the ability to set anomaly detection triggers on query durations/throughput.

[shairyar]

https://app.intercom.com/a/inbox/yzor8gyw/inbox/admin/4356044/conversation/16410700247151?view=List (private link)