Add DB related metrics to Prometheus

[lsulak]

Background

Maybe we can use something like this:

https://www.javadoc.io/doc/com.zaxxer/HikariCP/3.2.0/com/zaxxer/hikari/HikariConfig.html
https://medium.com/@ashah.dev.in/hikaricp-prometheus-metrics-explained-c16c960871ef
https://groups.google.com/g/hikari-cp/c/13hAm1xACP8?pli=1
The key file in probably TransactorProvider.scala where we setup Hikari connection, pool, and more.

Feature

We can see DB related metrics in Grafana.

Business Value

This is valuable to us because we will have much better visibility over the database's behavior. We recently had a production issue in which the PROD DB was under heavy load and the bottleneck was around connection pool. We didn't have this back then but would be incredibly useful.