Add CloudTrail event selector ingestion

[kunaals]

Summary

• collect CloudTrail event selectors for each trail
• expose event selectors on CloudTrailTrail nodes
• document event selector fields in schema

Testing

• python -m pytest tests/unit/cartography/graph/test_querybuilder_metadata.py -q
• python -m pytest tests/integration/cartography/intel/aws/test_cloudtrail.py::test_sync_cloudtrail -q (fails: Couldn't connect to localhost:7687)

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https://chatgpt.com/codex/tasks/task_b_68c35e7d9a1083238864a4e4628eb718