Improve readability of notebooks

[Shreyanand]

As a consumer of the time series I would like to have information presented in a more readable format.

There are two things to be done for this card:

• Split concepts notebook into two parts (concepts and modeling), Because of recent additions it has become very long.
• Follow this template for all the notebooks to make sure the content is coherent.

Sub issue #18

Template points to keep in mind:

• Proofread by other team member for grammar and spelling
• Proofread by other team member for coherence and reproducibility (does the analysis make sense as you read through the code and markdown from top to bottom?)
• Links checked and redirect correctly
• There is a top markdown cell describing what the notebook does
• There is a concluding markdown cell that summarizes the findings and outlines any next steps
• All plots are the same size
• All plots use seaborn (unless a specific functionality requires a different package)
• All plots have a title, labeled axis, and some written description of the insights uncovered in the graph
• Assuming correct environment, clicking "run all" works without error
• All cells have been run and their output is displayed
• Markdown headers are used to break up different sections
• No error or warning messages are present in the outputs
• All outputs are truncated to the minimum size required for explanation. No more than 20 rows.
• Cell execution counts are in order (a working "run all" was performed just before PR)
• All pre-commit checks pass