[feat] Expose metrics

[andrefurlan-db]

It would be good to directly expose metrics should as query time elapsed. Gotta think about more. If you have any ideas/suggestions please comment in this issue.

[fracasula]

It would be nice if an open standard is used to do this like OpenTelemetry for example. This way people can plug in whatever they want and have their metrics in their preferred backend (not just Prometheus but anything compatible with OTel).

Having the possibility to inject a MeterProvider should be good enough. If it's not provided by the user (i.e. it is nil) then the global one can be used (and if it's not configured then it's basically like a no-op meter provider).