Updating running cell after reconnecting

Hi all, @willingc
As described in issue #1150 when reconnecting (or even refreshing the page) to running a notebook the running cell isn't updating, this is a major problem for developers which run scripts which can take days to complete.
I can suggest a solution, you can take as an example google colab when you refresh the page or reconnect to the net the running cell keeps updating from the last point.

my setup:
connecting to Ubuntu server using ssh
my desktop: Ubuntu 18.04, python 3.6.8 (any extra info will be provided if required)

BR,
Aviv Shamsian

Start by reading issue #1150 and reproduce the behavior by refreshing or reconnecting to a notebook while a long-running cell is executing. Trace how the notebook reflects the running cell after reconnection; done means its status and updates continue to appear without interrupting execution.

Written by the indexing model from the issue text.