Speed up queries

Working on tpo/network-health/team#313 i filled up tpo/tpa/team#41558 so that a query that takes 50secs can work in grafana, but we should still speed up the queries by creating indexes for example.

We can collect here the slowest queries and how we can improve them.

Upldate: Let's progressively improve queries for different dashboards using different existing tables using child issues and leaving this one as parent.