[DOC] Create a more complete user example showcasing non-developer utilities

[teald]

Summary

The PyOpenSci review brought up that the examples in astrodata primarily focus on adding, manipulating, and utilizing tags and descriptors. Since astrodata has other features that are useful in data processing workflows, it'd be good to have an example that showcases working with data as a whole, using only astrodata & its dependencies.

To-do

• [ ]: Outline example process(es) and features they highlight
• [ ]: Source data (fake/generated or real, ideally non-Gemini)
• [ ]: Check what might be consolidated from User/Programmer Manuals (see Issue [DOC] Refactor/Rename User & Programmer Manuals #47)