Mostly this is just me testing out what it would look like to
modularize the app more… I've noticed that some concerns, like
fundraising, are just not relevant to most of the app, and being able
to lock them away inside subfolders feels like it'll help tidy up
long folder lists.
Notably, I haven't touched the models case yet, because I worry that
might be a bit more complex, whereas everything else seems pretty
well-isolated? We'll try it out!
Rather than figure out how to upgrade the Stripe gem to be compatible with future Rails, I'd rather just delete the references, since it's currently unused.
I'm not so bold as to go in and fully trash all our donation code; I just want to ensure we're not sending people down broken codepaths, and that if they reach them, the error messages are clear enough.