Blog post about Variant support

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**
- part of https://github.com/apache/arrow-rs/issues/4886

**Describe the solution you'd like**
Quoting @pauldix the cofounder and CTO of InfluxData, the recipe for success is:
1. write great software
2. Tell people about it

Many people including @scovich @klion26 @liamzwbao @codephage2020 @friendlymatthew and others have helped implement the first chunk of the Variant type which will be released in arrow 57.0.0:
- https://github.com/apache/arrow-rs/issues/6736

It would be great to have a writeup / public announcement about this great new feature on the arrow blog https://arrow.apache.org/blog/

The source is here https://github.com/apache/arrow-site

**Describe alternatives you've considered**

Here is an example post https://arrow.apache.org/blog/2025/07/18/recent-improvements-to-hash-join/
PR was here:
- https://github.com/apache/arrow-site/pull/667

**Additional context**