it's my opinion that we should be simply looking at the root of a project and we can detect all of the different dynamic content based on whether they have front-matter or not. The best applicable use-case for this is that in our carrot.is example, we're using `content_dir` to point at `blogging` but we have multiple different pieces of frontmatter like `press` and more. Perhaps `content_dir` is more appropriately `project_root` to allow you to pinpoint a directory like `blogging` but if it was blank, it defaults to `process.cwd()`?