Add limitations of Z Ordering to the blog post

Here's [the Z Order blog post](https://delta.io/blog/2023-06-03-delta-lake-z-order/).

We should add limitations of Z Ordering to this blog post, as discussed in [this post](https://medium.com/@stevejvoros/liquid-clustering-an-innovative-approach-to-data-layout-in-delta-lake-1a277f57af99).