I don't think there should be anything too controversial in here from a content perspective. This diff:
- Removes code that's no longer used in tutorial sections.
- Renames files and directories to match the new structure of the tutorial.
- Has the solids in the "complex pipeline" return single values instead of tuples.
- Uses f-strings in some places I missed them in my last rev.
- Fixes some typos and places where the code or screenshots did not match the language.