Improve performance

The new dashboard in v2 requires multiple aggregations and can therefore take longer to load. It's worth to take a closer look at the aggregations and GraphQL resolvers as there might be a lot to improve when it comes to performance.

- [ ] Check if it's possible to cache some data
- [ ] Check if there's data that is fetched multiple times from the database during one request
- [ ] Check why the recent aggregation is so slow
- [ ] Improve performance of facts and other GraphQL resolvers