Feature Request: XDG dirs setup: we'll create a bunch of directory structures for you

[jessebot]

I'm tired, but I had to write up a ticket for this before I forgot.

Describe the feature you'd like, and why

For users interested in a clean and organized home directory, they turn to the XDG Base Directory Spec by FreeDesktop. Many programs only kind of support the spec though, which leaves you needing to do things like create directories for them, or they won't work. I currently remedy this personally by having the default dotfiles have readmes in each directory that isn't automatically created, that way git does it instead, but it's cluttering that repo, and it should be done in this repo instead. It should be a config flag as well as a config file optional for users to disable, but set to True by default.