feat(childprocess): add new interfaces for tracking child processes

[Hweinstock]

Problem

Subprocesses are now tracked, by #6304, but this isn't visible to the user. Additionally, while the subprocesses are tracked in the logs, they aren't tracked in telemetry.

Solution

• add a command to spit this information out into the logs to make it visible to user.
• add telemetry to make this information visible to the dev team.

New Metrics

Upon investigation, it doesn't look like https://github.com/aws/aws-toolkit-common contains any metrics we can use.

ide_showExtStats :

aws-toolkit-vscode/packages/core/src/shared/telemetry/vscodeTelemetry.json

Lines 391 to 400 in b329ede

	{
	"name": "ide_showExtStats",
	"description": "Emitted when user invokes show extensions stats command",
	"metadata": [
	{
	"type": "numChildProcesses",
	"required": true
	}
	]
	},

ide_childProcessWarning :

aws-toolkit-vscode/packages/core/src/shared/telemetry/vscodeTelemetry.json

Lines 401 to 414 in b329ede

	{
	"name": "ide_childProcessWarning",
	"description": "Child Process warning due to high system usage",
	"metadata": [
	{
	"type": "systemResource",
	"required": true
	},
	{
	"type": "childProcess",
	"required": true
	}
	]
	},

Porting to commons: aws/aws-toolkit-common#962

Alternative Solution

• Display a proper table in a virtual document that we open (similar to cwl).

Pictures

---

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• Your code changes must meet the guidelines in CONTRIBUTING.md.
• License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[justinmk3]

Should we introduce it as a more generic Show Stats or Report Performance command? Even if it only has process stuff currently.

[github-actions]

• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.