Add a library of standard reducer steps (Basic CRUD)

There's no reason to make people write this themselves, especially considering they'd look pretty much the same for all applications.

Start by mapping the existing reducer and model-framework entry points, then review how the project uses Turnpike. Define the scope of the standard Basic CRUD reducer steps and how they should be verified against existing conventions. The issue names no files or tests, so completion criteria need clarification.

Written by the indexing model from the issue text.