feat: omit metadata columns

[parisni]

Important Read

• GitHub issue: TBD

What is the purpose of the pull request

This pull request adds an option to omit Hudi metadata fields during sync, including config support and tests.

Brief change log

• Added config flags to control omission of Hudi metadata fields.
• Plumbed the omit option through Hudi conversion and schema extraction.
• Added unit tests for config parsing and metadata-field filtering.

Verify this pull request

This change added tests and can be verified as follows:

[vinishjail97]

Can we enable this config for the schema evolution test in ITConversionController ?
I have a hunch that iceberg read might fail.

[vinishjail97]

We won't find OMIT_METADATA_FIELDS_CONFIG in hadoopConf..so just keep the change restricted to Properties?

[parisni]

Done

[parisni]

Can we enable this config for the schema evolution test in ITConversionController ? I have a hunch that iceberg read might fail.

you are right the test expect the _hoodie_record_key so if we omit the column it will fail https://github.com/apache/incubator-xtable/blob/main/xtable-core/src/test/java/org/apache/xtable/ITConversionController.java#L947

Not sure what's the problem here, it's a test expectation, not a iceberg expectation