ui: add cluster/per-node toggle to time series charts

[couchand]

Adds a toggle to switch between cluster-wide aggregated data and per-node data for many of the charts on the time series dashboards.

Fixes: #14598
Fixes: #18452
Fixes: #20571

New:

Old:

[cockroach-teamcity]

This change is 

[Amruta-Ranade]

Yay for landing the PR 🎉

First impressions: It might be just me, but the Cluster/Node drop-down and Cluster-Per Node toggle seem incredibly confusing. I know they are supposed to serve two different functions. Is there a way we can make the nomenclature reflect the difference?

[vilterp]

I like the simplicity of this approach, but I was surprised when I toggled to per-node mode and saw that multi-metric graphs didn't expand into num metrics graphs, each with one series per node, and just chose one of the metrics instead (e.g. sql.query.count instead of {selects, inserts, updates, deletes} and replicas instead of {replicas, quiesced}). Maybe it wouldn't be too much work to do the "multiple charts for different metrics in one card" design from the other PR? Let's discuss more…

[josueeee]

I agree with this observation. It is confusing and we should discuss how we can rearrange the order of the menu to make it easier to understand along with better nomenclature. There's also some design polish to be made on the labelling of the per-node charts.

First impressions: It might be just me, but the Cluster/Node drop-down and Cluster-Per Node toggle seem incredibly confusing. I know they are supposed to serve two different functions. Is there a way we can make the nomenclature reflect the difference?