Jupyter Notebook Improvements

[alxmrs]

Here is a list of feedback on our walkthrough notebooks from our team, in no particular order:

• Add a warning in the Surface-Walkthrough that regridding takes a long time
• In the model-level notebook, add a brief description of weather events happening on each datestring
• Add extra instructions on how to authenticate in the details view, in case users hit permissions issues (i.e. application-default login).
• In each notebook, document what a chunk means, and where the 48 number comes from.
• Add labels & comments to figures
• Improve plotting & visualization, especially better plotting projections
• Delete extra cells in the notebooks
• ML Notebook copy: have all the variables in the same order as how XArray prints them. E.g.: Have the var shorname be a prefix for the description
• Add a note to the ML notebook on what the dimensions mean, esp. vertical levels
• Add a "looking ahead" or conclusion section to the end of the ML notebook
• Make sure the checked-in version of the ML notebook includes plots.