Blog post for the DataFusion `55.0.0` release

### Is your feature request related to a problem or challenge?

- Part of https://github.com/apache/datafusion/issues/22393

Rendered preview: https://alamb.github.io/datafusion-site/blog/2026/08/16/datafusion-55.0.0/

### Describe the solution you'd like
- Follow the model of https://github.com/apache/datafusion/issues/22392

Let's tell the world what we have done since the [DataFusion 54 release blog](https://datafusion.apache.org/blog/output/2026/06/12/datafusion-54.0.0/)

Here is the last blog:
- https://datafusion.apache.org/blog/output/2026/06/12/datafusion-54.0.0/
- https://github.com/apache/datafusion-site/pull/197

We can start with the features listed on the current release ticket
- https://github.com/apache/datafusion/issues/22393