GH-3070: Add Variant logical type annotation to parquet-java

[aihuaxu]

Rationale for this change

This is to add Variant logical type in parquet-java to be used by dependent projects.

What changes are included in this PR?

Variant logical type is added to LogicalTypeAnnotation.

Are these changes tested?

Yes.

Are there any user-facing changes?

Yes. Variant logical type is available.

Closes #3070

[aihuaxu]

@Fokko, @wgtmac Can you help check if this is right implementation? Thanks.

[wgtmac]

Do we need to support writing and reading variant data?

[aihuaxu]

The Variant reading and writing are getting implemented in Iceberg and/or the engines themselves. I think later we can think of pulling the implementation to Parquet if needed.

[emkornfield]

The Variant reading and writing are getting implemented in Iceberg and/or the engines themselves. I think later we can think of pulling the implementation to Parquet if needed.

I think this is problematic if the spec lives in parquet and doesn't have a complete implementation per previously agreed upon guidelines for new parquet features. This probably warrants a discussion on the mailing list. CC @julienledem @rdblue @RussellSpitzer