Arthur Silva Sens

I'm gonna work on a new PR implementing the e2e-tests for feature gated features. I'll come back to this one afterwards :)

Ok, the PR is blocked until we get #6665 in, but I believe all other comments are addressed

This should be ready for another round of reviews :)

Anything I could do to help with the reviews? :)

> While reviewing, I wonder what should happen for Prometheus rules. Should they be deployed to scaled-down shards? My intuition says no (for instance, alerting rules usin `absent()` could fire)...

So... is anything missing in this PR? Besides the current conflicts? I'll try to solve them today or tomorrow :)

> I have some comments on the API definition but I tested locally and it worked fine. One thing I've noted is that the status subresoure shows (as expected) only...

A metric could also be used :) https://github.com/prometheus/client_golang/blob/main/examples/versioncollector/main.go

We could easily fix that by adding an option for adding extra labels/annotations in the [Alerting spec](https://github.com/pyrra-dev/pyrra/blob/49411657dcb582533c69f32110ed400de9ef2706/kubernetes/api/v1alpha1/servicelevelobjective_types.go#L116-L133)

> The original reasoning for having them as CRD labels is to make filtering via `kubectl get slo -l pyrra.dev/team=backend` possible. I wonder how much usage that feature has in...