[Variant]: Implement DataType::Interval support for cast_to_variant kernel

[codephage2020]

Which issue does this PR close?

We generally require a GitHub issue to be filed for all bug fixes and enhancements and this helps us generate change logs for our releases. You can link an issue to this PR using the GitHub syntax.

• Closes [Variant]: Implement DataType::Interval support for cast_to_variant kernel #8056 .

What changes are included in this PR?

Added Interval Support:

• IntervalYearMonth → Variant::Int32
• IntervalDayTime → Variant::Binary (8 bytes)
• IntervalMonthDayNano → Variant::Binary (16 bytes)

Are these changes tested?

Yes.

Are there any user-facing changes?

No.

[alamb]

Thank you @codephage2020

[alamb]

I think if you made this Variant::Binary(bytes) you could then use the existing run_test function rather than adding run_binary_interval_test

[alamb]

I double checked that there doesn't seem to be a interval / duration type in Variant: https://github.com/apache/parquet-format/blob/master/VariantEncoding.md#encoding-types

Converting to Int32 / VariantBinary is about the best we can do for now. However, it might be misleading

Another behavior might be to throw a "InvalidArgument" Error and make it clear that casting from Intervals to Variant is not well defined / supported.

What do you think?

[codephage2020]

You're right. I think throwing an InvalidArgument error is the better choice.
It's more honest and prevents silent data corruption or misinterpretation.

Let's modify it.

[alamb]

Thank you @codephage2020