Add comprehensive Apache Iceberg table format guide

[Copilot]

This PR adds a comprehensive guide to Apache Iceberg table format and other modern table formats, addressing all aspects requested in the issue.

What's Added

New File: iceberg-table-format.md

• Complete guide covering Apache Iceberg, Delta Lake, Apache Hudi, and Apache Kudu
• Nearly 4,000 words of detailed technical documentation
• Code examples and real-world use cases

Content Covered

The guide comprehensively addresses all 10 questions from the issue:

1. What is Iceberg? - Detailed explanation of the open-source table format specification
2. Why table formats are necessary? - Problems with raw file approaches and how table formats solve them
3. Who created Iceberg? - Netflix's history, key contributors, and development timeline
4. Features with examples - ACID transactions, schema evolution, time travel, partition evolution with code samples
5. Benchmarks - TPC-DS results, Netflix/Adobe case studies, performance metrics
6. Cloud provider support - AWS (EMR, Glue, Athena), GCP (BigQuery, Dataproc), Azure (Synapse, Databricks) with implementation examples
7. Competing formats - Delta Lake, Apache Hudi, Apache Kudu
8. Detailed comparison - Feature matrix, use cases, benchmarks for all formats
9. Decision framework - When to use what with decision tree and guidelines
10. Hello world examples - Complete code examples for all table formats (Python/Scala/Java)

Key Features

• Practical code examples for each table format
• Performance benchmarks with real-world metrics
• Cloud service integration examples
• Decision framework to help choose the right format
• Migration strategies from traditional approaches
• Best practices and recommendations

The guide follows the repository's documentation style with clear explanations, practical examples, real-world use cases, and references for further learning.

Updated: README.md to include the new guide in the Machine Learning & Data Science section.

Fixes #86.

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