Hi Fabian,
The module resource folder is initially only included in a jar file. It will be extracted at runtime by our JSF Resourcehandler extension. Therefore only resources, which are requested by JSF can be located in module resource folder.
There might be an option, which I haven't verified yet: The module DPU for sure can also include an additional war file, which have an own context root. This would lead to absolute URI to use to read the Javascript. But it would be part of your module! As said I haven't test it, but it should work!
Hope that helps.
Regards Wolfgang