AngularJS sources missing in sources jars

The generated source jar for maven modules with AngularJS apps do not contain the (javascript/css/png etc.) sources.
This is because these sources are located under $moduleRoot/js, so the maven-sources-plugin is blind to those files.

I see 2 solutions (there might be more):

• move the AngularJS sources into src/main
• change the maven-sources-plugin to include the files.

The maven modules affected are

• addon-channelmanager/frontend (on trunk and datatrack branch)
• addon-channelmanager/angularjs-api (on datatrack branch)
• targeting/frontend (on datatrack branch)

I'm not sure if this issue is serious enough to backport.