[API]Creation of folders with the PluginAPI.writeScore method

When attempting to write a score located on a folder that doesn't exist with PluginAPI.writeScore, an error is raised.
The request is about having this method creating all the necessary folders instead of failing.

var target="path/to/somewhere/idontexist/myscore.pdf"
if (!writeScore(curScore, target, "pdf") // --> return false, and the file "myscore.pdf" does not exist
console.log("Could not write " + target);
}

This request comes after the discussion Creating folders from a plugin.

It appears that there is no ways in QML/javascript to create folders (see this question on Stack Overflow).

The current workaround is non platform-agnostic solution that should therefore avoide.

The recommended approach is to delegate these tasks to backend objects.
PluginAPI.writeScore is good candidate for this.