Find better way of dealing with host-specific files

Perhaps using a directory structure like `[package]/host/[hostname]/[file]` instead of `[package]/[file].[hostname]` would be better since it's more generic, not as reliant on custom file-naming schemes, better to discover automatically (e.g. this schema wouldn't require declaring every host-specific file in the `dotpkg.json`), better supported in editors and on OSs like Windows that rely on file extensions?