Add support for attribute renaming/deletion in the schema conversion

[gdlg]

This pull request introduces a new post-processing step to the schema conversion logic in the converter registry, ensuring that attribute renaming and deletion are handled explicitly after all field-type conversions. The main change is the addition of the AttributeRemapperConverter, which is used internally to finalize attribute names and drop unused attributes, improving the correctness and flexibility of schema conversions. The conversion path finding logic and related tests have been updated to reflect this new step, and some minor improvements were made to the converter implementation details.

Converter registry and path finding improvements

• Added AttributeRemapperConverter, a special converter that performs attribute renaming and selection (dropping others) as a post-processing step after field-type conversions. This converter is not registered globally but is used internally by the conversion path finder.
• Updated the A* search and conversion path logic to append an AttributeRemapperConverter when attribute names or the set of attributes do not match the target schema, ensuring that the output schema is correct. [1] [2]
• Modified _SchemaState equality and hashing to ignore attribute names, focusing only on field types and their properties, since renaming is now handled in post-processing.
• Improved _get_applicable_converters to simplify the logic and ensure uniqueness of temporary names during conversion steps. [1] [2]
• Updated the heuristic cost function to ignore attribute names, as they are now fixed in post-processing. [1] [2]

Converter implementation details

• Minor changes to image converters to handle shape column renaming consistently, reflecting the new attribute remapping logic. [1] [2] [3]

Testing updates

• Added AttributeRemapperConverter to the test imports and updated all relevant tests to expect an additional converter in the conversion path, verifying that attribute remapping is performed as a final step. [1] [2] [3] [4] [5] [6] [7] [8] [9]

Summary

How to test

Checklist

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