Add CPU profiling and component-level diagnostics

[fearful-symmetry]

What does this PR do?

Follow-up to elastic/elastic-agent-client#80

Part of #2140 and #2141

NOTE: Before the above two issues are actually closed, after we merge this we also need to update elastic-agent-client in beats itself.

This PR accomplishes a few things:

• makes changes to the agent control protocol to add a DiagnosticComponentsRequest call and an AdditionalDiagnosticRequest request field. This allows us to request an optional CPU profile to the diagnostic bundle.
• A number of changes to the coordinator, diagnostics command, and manager to support component-level diagnostics.
• An additional integration test
• Increase the timeout for diagnostic requests
• Restructures the .zip files that elastic-agent produces, so component-level diagnostics are properly placed in the components/ directory, and not copied per-unit
• Add a CPU profile diag hook for the agent itself

It should be noted that codepath for component diagnostics is different from the normal unit-diagnostics in a number of ways:

• The manager PerformComponentDiagnostics method returns an error value, the corresponding unit-level diagnostic does not
• The component level diagnostic aggregator works in parallel, spawning a go routine for every component that requires diagnostics. As CPU profiles run for a set period of time, this is kind of needed so diagnostic request doesn't take 3 minutes.

Why is it important?

We want CPU profiling in diagnostics

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

How to test this PR locally

• Pull down and build in whatever way you normally would
• run elastic-agent diagnostics -p

[elasticmachine]

Pinging @elastic/elastic-agent (Team:Elastic-Agent)

[mergify]

This pull request does not have a backport label. Could you fix it @fearful-symmetry? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 8./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[elasticmachine]

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• Start Time: 2023-07-28T17:17:35.486+0000

• Duration: 27 min 7 sec

Test stats 🧪

Test	Results
Failed	0
Passed	6153
Skipped	31
Total	6184

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	98.718% (77/78)	👍
Files	68.75% (187/272)	👍 0.093
Classes	67.659% (341/504)	👎 -0.349
Methods	54.064% (1071/1981)	👎 -0.266
Lines	40.262% (12296/30540)	👎 -0.113
Conditionals	100.0% (0/0)	💚

[blakerouse]

Change looks good.

A couple comments, I believe the one for stoping the CPU profile on context cancellation needs to be fixed before merge.

[blakerouse]

Updates look great!