[Alerting] Surface rule execution durations in rule details

[ymao1]

POC here

As part of the effort to address long-running rules, we would like to surface rule execution duration information (currently stored in the event log) in the UI.

With this PR, we are surfacing it in the Rule Management View. This issue covers surfacing it in the Rule Details view.

In the rule details view. We can calculate statistics for avg/min/max duration for all the retrieved event log entries in the getAlertInstanceSummary function and show them in the UI. We could also show a warning if the average execution duration for the rule greatly exceeds the configured schedule (for example, if the rule is scheduled to run every minute and the average duration is 25 minutes, we should tell the user!)
Example:

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[ymao1]

@mdefazio I have split out the Rule Details view into its own issue. When you are ready with the mockup, can you post to this issue? Thanks!

[mdefazio]

Here are some initial thoughts on how to show these values in the detail page. I've taken some cues from Security's Host page and how they show metrics there (with some obvious slight differences since we want to show 3 values in relation to a single chart, compared to 1 value per chart on the Hosts page).

I'm including a dropdown to provide the user the ability to show last 60, last 120, etc (or whatever count we determine is best here). This may be out of scope, so i'm fine omitting it for now. We may want some indication that we are only showing the last 60 executions (assuming this is also the case for the alerts table on this page)?

I've grayed out the alert table as these mockups are only meant to focus on the addition of the metrics above the table.

Video walkthrough:
https://user-images.githubusercontent.com/3756330/136995977-a1136356-0252-421a-873b-3180eea25c27.mp4

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Screenshots:

No data

Only a few executions
I think it will be easier to read and understand if the bars for the execution chart are always in relation to 60 (as opposed to a single bar filling the width of the chart). Let me know if this poses issues though.

At least 60 executions

Warning message within values
Also showing what this may look like if we wanted to show more than the last 60 executions

[mdefazio]

Here are updated mockups that show the following metrics:

• Last response
• Average duration
• Execution duration chart (with average indicator)

If the average duration exceeds the rule interval schedule, then I think we should show a warning on this panel.

Default view:

Warning panel and tooltips: