STANBOL-897: simplifying code (and generalizing) by providing a graph response rather than serializing to a String. Settinng dataTypein ajax request to make sure Accept is html (alternative would have been an @Produces on getCreateUserForm)

git-svn-id: https://svn.apache.org/repos/asf/stanbol/trunk@1457490 13f79535-47bb-0310-9956-ffa450edef68