Port over relevant material from main workshop #2

The idea for this taster is to use Jupyterlab notebooks to do this two hour session, with most of the first hour material a compressed version of the workshop, around Napari UI, basic info on images and basic image analysis operations to do instance segmentation.

For the second hour, we will look at AI methods to do the instance segmentation.
This issue will focus on porting the existing material into shorter episodes, with a focus on Jupyterlab for delivery.