Removing _module.js files which (despite their name) don't describe m…

…odules at all, but rather describe javascript namespaces (ex: dojo/dnd, dijit/layout, dojox/widget). These files don't really have a place in the AMD world, and that information is already in the reference guide and/or the package manifest files for packages registered in packages.dojofoundation.org.

Refs #13101

git-svn-id: http://svn.dojotoolkit.org/src/dojox/trunk@28697 560b804f-0ae3-0310-86f3-f6aa0a117693