[FEATURE] sap.m.DisplayListItem: Added right to left support

- Added valueTextDirection property which accepts value of type
sap.ui.core.TextDirection
- Renderer adds dir attribute to the value element with the respective
valueTextDirection
- Dedicated qunit file for the control with qunit tests for the RTL
support

Change-Id: Ia954223f9a7d7b6022e7f54e1a9c5c8565efa1be