Pinned Rows API

## Use case

Hello! I would like to request a `Pinned Rows API`. You already have a `Pinned Columns API`, which works nicely.
By the way, I’ve noticed that you also have a `Summary Rows API`. I tried to use it, but it is designed for a different purpose.

## Proposed solution

We have a lot of rows: `A, B, C, ..., Z`. I want to pin `row K` to the top or bottom so I can:

* See it while scrolling the table
* Edit it
* Have it disappear from the unpinned rows (basically moved to the pinned view)
* Define its height, similar to `header` or `summary` rows

Essentially, I expect the same approach as for the `Pinned Columns API`, but applied to rows.