default Map<String, Object> getRefJobContent() {
        return (Map<String, Object>) getParameter("refJobContent");
    }
This is the content of the third appConn returned, when the RefCreationOperation is called.
the third-part AppConn usually will call this method to get refJobContent to do some operation.
@return a refJobContent related a only third appConn refJob
dss-standard/development-standard/development-process-standard/src/main/java/com/webank/wedatasphere/dss/standard/app/development/ref/RefJobContentRequestRef.java