Filesystem permissions for a branch.

This is reused for the private and public permissions.

Filesystem permissions.

```elm
import Webnative.Path as Path


{ private =
    { directories = [ Path.directory [ "Audio", "Mixtapes" ] ]
    , files = [ Path.file [ "Audio", "Playlists", "Jazz.json" ] ]
    }
, public =
    { directories = []
    , files = []
    }
}
```

Permissions to ask the user. See AppPermissions and FileSystemPermissions on how to use these.