[Security Solution] Implement array of objects diff algorithm

[jpdjere]

Epics: https://github.com/elastic/security-team/issues/1974 (internal), https://github.com/elastic/kibana/issues/174168

Summary

Implement an algorithm for diffing and merging changes in array of objects type of fields of detection rules.

Context from the Rule Customization RFC:

• Concrete field diff algorithms by type
• Array of objects fields

To do

• [ ] Step 0
  • [ ] Make a proposal which fields should use this algorithm. Get feedback and approval from the team.
• [ ] Step 1 (separate PR)
  • [ ] Implement the algorithm and cover it with unit tests.
• [ ] Step 2 (separate PR)
  • [ ] Apply the algorithm to a few rule fields. It will become used in the upgrade/_review endpoint.
  • [ ] Write a test plan covering rule upgrade scenarios for the fields to which the algorithm has been applied.
  • [ ] Add test coverage according to the test plan (integration tests, primarily?).

[elasticmachine]

Pinging @elastic/security-detections-response (Team:Detections and Resp)

[elasticmachine]

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

[elasticmachine]

Pinging @elastic/security-detection-rule-management (Team:Detection Rule Management)