Create guide for new figure/table developers

[Copilot]

Create a figure/table workflow guide and add it to the bottom of CONTRIBUTING.md.

[Schiano-NOAA]

This is a great start! I made some comments and suggestions for changes. I think the last thing it needs is a mention that all figures or tables get returned at the end of the function regardless if it's exported or not. The contributor does not need to add return() of the table or figure when it's at the end of the function.

[sbreitbart-NOAA]

This is a great start! I made some comments and suggestions for changes. I think the last thing it needs is a mention that all figures or tables get returned at the end of the function regardless if it's exported or not. The contributor does not need to add return() of the table or figure when it's at the end of the function.

Thanks so much for your helpful comments, Sam. I've updated the guide to address your comments, including how figures/tables are returned even if they're not exported.

[Schiano-NOAA]

Fantastic!