[Security Solution][Telemetry] Refactoring security telemetry task code

[tsouza]

Summary

Over the past releases we've introduced a few Kibana task classes for supporting security solution telemetry. In its current versions there seems to be some code duplication. This PR is an effort for refactoring these classes and simplify things.

Change summary:

1. Removed all duplicate/redundant code from the task classes defined in tasks and consolidated them in a single task class defined in task.ts. The code that remained within tasks is the logic that is particular to each telemetry task.
2. Wrote a new test suite in task.test.ts for the new reusable task class defined in task.ts. The new test suite uses a dummy task definition and it tests basic capabilities such as being able to register a task and decide if a task should run or not depending if telemetry is opted in or out.
3. Simplified the test for the task in tasks. The tests now focus on the specific logic for each class. For now, the tests only verifies if methods that fetches data is being properly called. This is because the telemetry data structure that the telemetry classes work with are fairly complex and it would be time consuming to write sample/fake versions of this data to properly test other method calls. We should revisit and improve tests in a future iteration.

To Do:

• Improve task tests.
• The TelemetryEventsSender class still spawns a rogue telemetry channel that runs entirely different from the other task. We should also try to bring this into Kibana task manager.

Checklist

Delete any items that are not applicable to this PR.

• Unit or functional tests were updated or added to match the most common scenarios

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[tsouza]

@elasticmachine merge upstream

[pjhampton]

@elasticmachine merge upstream

[pjhampton]

I really like where this is going. Great job! 🚀

Can't really fault it. I pulled down your code and ran it against ES. Tasks still run as expected and opt-in/out functionality working as expected.

Please address my comment and incorporate #113239 when it is to be merged today! ✨

[tsouza]

@elasticmachine merge upstream

[kibanamachine]

merge conflict between base and head

[pjhampton]

🌔 🚀 ✨ LGTM ✨ 🚀 🌔

[tsouza]

@elasticmachine merge upstream

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 7307b70
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Metrics [docs]

✅ unchanged

History

• 💔 Build #160026 failed 7eea6d2
• 💔 Build #159898 failed 79bc872
• 💔 Build #159902 failed 38fe3ed
• 💔 Build #159757 failed 410b94e
• 💚 Build #159459 succeeded 7674b57

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	7.x

This backport PR will be merged automatically after passing CI.