Usage of tokenized variables in RStudio Connect Apps

I'm curious how people handle the use of tokenized variables with RStudio Connect. Support has been somewhat vague, referencing that our R apps should use the config R Package, but I'm not understanding how exactly that fits into the mix.

I was also unsure if the Environment Variables you can set in the publish GUI were intended to be used for this, but it seems like a pain to have to set multiple variables per app manually.

So let's say I have two RStudio Connect servers, Production and Development. I'm trying to figure out how I can tokenize information like: apps deployed to the Development RStudio Connect server should point to test-database with username test and password testpass, and apps deployed to Production RStudio Connect server should point to prod-database with username production and password productionpass. Ideally it would be nice if it could pull from a centralized encrypted file or database so we could do things like rotate passwords by making one change.

I've seen some indication that R has a vault package, but I haven't dug into it and wasn't sure if that would work as expected.