Introduce EntityBase#setLastModified(long)

Change-Id: Ib01d42457fe6012da89aec62fad54c2374a2f5fb
Signed-off-by: Michael Ochmann <michael.ochmann@sap.com>
Render lastModifiedMillis attribute

Change-Id: Ie628b1f6a944ce787089749c2f8e3749c3ecd478
Signed-off-by: Michael Ochmann <michael.ochmann@sap.com>