users/customers do not have a reasonable number of buckets anymore,
this is why we must avoid overpopulating cluster endpoints, instead
move the bucket monitoring to a separate endpoint.
some of it's a breaking change here for a couple of metrics, but
it is imperative that we do it to improve the responsiveness of
our Prometheus cluster endpoint.
Bonus: Added new cluster metrics for usage, objects and histograms
PR #15052 caused a regression, add the missing metrics back.
Bonus:
- internode information should be only for distributed setups
- update the dashboard to include 4xx and 5xx error panels.
