Merge repetitive aggs, use filtered aggs where possible, remove unused expressions and datasets

[cpcloud]

Hm, I think this will need some fixes. I can put those up tomorrow morning.

[lostmygithubaccount]

it ran fine for me, running now from the schedule so we should see in a few minutes: https://github.com/ibis-project/ibis-analytics/actions/runs/6460183827