Migrate ingestion and table handling workflow from Delta Lake to Apache Iceberg

[khanahmedm]

This PR introduces foundational Apache Iceberg support across the ingestion and orchestration workflow by refactoring Delta-specific implementations and updating related unit tests and documentation references.

Key Changes

Core updates

• Replaced get_minio_client with get_s3_client
• Updated related tests and fixtures

Iceberg migration

• Refactored table handling logic from Delta Lake to Apache Iceberg
• Updated initialization utilities and orchestration logic
• Migrated write operations to use the Iceberg writeTo() API

Table processing updates

• Updated write_table usage to align with the new function signature
• Adjusted orchestration and batch processing tests accordingly

Model and documentation cleanup

• Removed Delta-specific terminology from models.py docstrings
• Updated comments and internal references to reflect Iceberg support

Test updates
Refreshed affected unit tests across:

• test_core.py
• test_init_utils.py
• test_io_utils.py
• test_table_processor.py
• test_table_batch_processor.py
• conftest.py

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.71%. Comparing base (eb24219) to head (539987c).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop      #72      +/-   ##
===========================================
+ Coverage    97.51%   97.71%   +0.19%     
===========================================
  Files           18       18              
  Lines          966      962       -4     
===========================================
- Hits           942      940       -2     
+ Misses          24       22       -2     

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