Add an optional chime/notification for end of execution

### Problem

I would like it if a notification appeared and played a chime happened when my batch of cells finished executing because then I would know when my code was finished executing, without needing to constantly pay attention to it.

### Proposed Solution

Add an option so that when all cells have finished executing, a notification will appear and play a chime or sound

### Additional context

Jupyter-Notify solved this by adding some cell magic to send a notification when a single cell is finished executing, but the user has to manually decide which cells to receive notifications about. Instead, I would like to have an option to send a notification to me when the whole batch of cells I'm executing finish.

It would also be useful if a different sound played if one of the cells had an error or exception

This should be an optional setting that users can turn off easily

The issue names no files, tests, or entry points. Review Jupyter-Notify and the notebook's existing cell-execution behavior first, then determine where an optional end-of-batch notification and distinct error sound would belong. Done should include an easily disabled setting, notification and chime after the batch completes, and different behavior when a cell errors.

Written by the indexing model from the issue text.