Enable datasets with custom formats

[AnuradhaKaruppiah]

Description

Closes: #352
This PR enables custom dataset formats by adding a new EvalDatasetCustomConfig class that allows users to specify custom Python functions for dataset transformation. The implementation provides a standardized interface for custom parsers while maintaining compatibility with existing functionality.

Adds EvalDatasetCustomConfig class for custom dataset handling
Implements custom function loading and execution with error handling
Adds preprocessing utilities to apply standard filters and transformations
Includes example implementation and documentation

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[Copilot]

Pull Request Overview

This PR enables custom dataset formats by adding a new EvalDatasetCustomConfig class that allows users to specify custom Python functions for dataset transformation. The implementation provides a standardized interface for custom parsers while maintaining compatibility with existing functionality.

• Adds EvalDatasetCustomConfig class for custom dataset handling
• Implements custom function loading and execution with error handling
• Adds preprocessing utilities to apply standard filters and transformations
• Includes example implementation and documentation

Reviewed Changes

Copilot reviewed 11 out of 14 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/aiq/data_models/dataset_handler.py	Adds EvalDatasetCustomConfig class with dynamic function loading and includes it in the union type
src/aiq/eval/dataset_handler/dataset_handler.py	Implements custom dataset handling logic and refactors preprocessing into reusable methods
examples/evaluation_and_profiling/simple_calculator_eval/src/aiq_simple_calculator_eval/scripts/custom_dataset_parser.py	Provides example custom dataset parser function
examples/evaluation_and_profiling/simple_calculator_eval/src/aiq_simple_calculator_eval/configs/config-custom-dataset-format.yml	Configuration example for custom dataset usage
docs/source/reference/evaluate.md	Documents the custom dataset format feature