[Infra UI] Metrics Explorer set graph's scale adaptive to metric's values

[sorantis]

User Story:

As a Metrics Explorer user I want the graphs for queried metrics scale adaptively to the min/max range of the metric's value so that I could easily observe system's behavior.

The feature:

When graphing a metric in Metrics Explorer, the resulting graph's Y-axis always starts at 0. In some cases, when the metrics' values are quite large, this ends up looking like this:

The same graph, when opened in Visualise looks scaled down to the metric's min/max + some margin:

From the UX perspective the second graph look more informative as it's easier to observe (in this case) memory usage.

[elasticmachine]

Pinging @elastic/infra-logs-ui

[jasonrhodes]

For context: we've thus far kept a pretty firm opinion in observability graphs that the Y-axis should always start at 0, to prevent creating misleading graphs. Worth having another conversation about this perhaps but I think there's value in that argument.

[sorantis]

Thanks for clarifying @jasonrhodes. I'd interested to hear the supporting arguments.
In some cases (like the one above) measurements really don't fluctuate very much and with a graph that starts at 0 users find it hard to detect these changes/trends.