Allow dragging notebook cells to new positions

[okennedy]

What pain point is this feature intended to address? Please describe. Sometimes the content of a cell needs to be moved elsewhere in the notebook. It would be helpful if cells could be moved around.

Describe the solution you'd like

Add some sort of affordance (handlebars?) to indicate that cells can be moved and allow dragging by e.g., their left bar.

Describe alternatives you've considered

The alternative is to delete and (manually) re-create the cell at the new position.

Additional context Add any other context or screenshots about the feature request here.