Implement Variant writer

### Describe the enhancement requested

Add support to write shredded Variant values to Parquet based on the spec in https://github.com/apache/parquet-format/blob/master/VariantEncoding.md and https://github.com/apache/parquet-format/blob/master/VariantShredding.md

### Component(s)

_No response_