FOX-3765: Add support for sns publish batch

[thomet]

This pull request introduces batch event publishing support for AWS SNS in the EventQClient, improves code clarity, and updates dependencies. The core enhancement is the addition of methods to efficiently publish multiple events in a single SNS request, along with comprehensive tests to ensure correct behavior.

AWS SNS Batch Publishing:

• Added raise_events_batch and publish_batch methods to EventQClient for publishing multiple events in batches to AWS SNS, handling chunking to comply with SNS batch size limits and supporting per-event context overrides. [1] [2]
• Introduced helper methods (publish_batch_entries, batch_entry_values, prepared_message) to serialize and prepare batch entries for SNS.

Testing:

• Added extensive RSpec tests for batch publishing, including payload serialization, batch chunking, and context overrides, ensuring robust coverage of new batch methods.

Code Quality and Maintenance:

• Refactored initialization logic for clarity and conciseness in EventQClient.
• Improved logging formatting for SNS and SQS publishing methods for better readability. [1] [2]
• Updated the EVENTQ_VERSION to 4.4.1.
• Updated the Dockerfile to use openssl-dev instead of libressl-dev for better compatibility.

Documentation:

• Added .github/copilot-instructions.md with instructions for maintaining and interpreting the AI_ATTRIBUTION.md log.