Use rstudioapi in saving.R

[jonthegeek]

Rather than having users edit saving.R to fill things in, put code there that they can execute. Detect whether they're in rstudio (or positron), and, if so, use {rstudioapi} to figure out what folder we're in, and ask them in the console if we can't figure it out. We'll need them to provide the dataset objects, but I think we can make that work via questions in the console, even.

Consider using this for lots of things, although still have them edit the intro.md directly (but we could open it for them).

Maybe this should even be a Shiny app?