CF-165/CF-290: add wadl

Add the preferences-service WADL. @bwtaylor, @ChandraAddala, @usnavi, please review. 

I plugged the WADL into my Repose running on iNova. It was able to forward the request to the service.
The way the service is designed, "archive_prefs" is actually a dynamic string. http://localhost:8080/metadata/{resourceTypeId}. I dont know how you specify that in a wadl