[INTERNAL] sap.ui.model.odata.AnnotationHelper#simplePath

Add helper method which omits types and constraints because a SmartField
handles this itself.

Change-Id: If731504a7c7720a844a98ebce19887d94b31be4e
JIRA: FLPUISERVICES2014-1163
Merge "[INTERNAL] sap.ui.model.odata.AnnotationHelper#simplePath"