Useful feature for demoing what errors look like

Having a way to execute all cells and continuing after hitting an error can be useful for demoing what an error would look like in a presentation context. This would be a nice action to have in the notebook interface (especially once customised with a keyboard shortcut).

Start from the notebook interface and the current cell-execution behavior. Done means an action can execute all cells, continue after an error, and be assigned a keyboard shortcut.

Written by the indexing model from the issue text.