Partials are nice, but blocks are a better base construct. Right now there is basically only layouts/_default/baseof.html that is doing most of the work. See: https://gohugo.io/templates/blocks
For now the only singles we need are posts, so it makes sense to move this there. I can make another single template for pages later.
Some file are empty (created by `hugo new theme`), but I've left them for reference later.