Docuemnt setup for chifra slurp --source

[tjayrush]

Can you please add some docs to chifra slurp as far as how to set up the keys?

1. Add a note to ./src/dev_tools/goMaker/templates/cmd-line-options.csv. Under the notes, add a new note referring to the README
2. To a file called ./src/dev_tools/goMaker/templates/readme-intros/slurp-notes.md add information about how to configure keys (use chifra config edit)
3. Run make generate. It should update a number of files.
4. One of the files is ./src/apps/chifra/internal/slurp/README.md. If the README makes sense, the rest of the code should be good.

Commit and merge.