JBIDE-1354 to allow for additional types of filesets.
1) Maintain backwards compatibility in terms of reading legacy files stores and functioning properly
2) If user makes a change, save in new persistance format
3) Add core elements for a 'module id' based classpath provider, only for jboss servers that have jboss-modules as a base
4) Expand UI to allow creation of a classpath element by using a module id instead of a basedir/includes/excludes pattern
Out of scope for this issue: Core/UI for a per-facet customized response.