Add screenContext native property

Retrieving it via some other screen object can be painful especially
when there isn't a readily available screen object to use.

Change-Id: If13e808435ea6f2909d5b4c3c5c736950e00aa5a
Reviewed-by: Dan Cape <dcape@qnx.com>
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>

src/plugins/platforms/qnx/qqnxnativeinterface.cpp

@@ -91,6 +91,9 @@ void *QQnxNativeInterface::nativeResourceForScreen(const QByteArray &resource, Q
 
 void *QQnxNativeInterface::nativeResourceForIntegration(const QByteArray &resource)
 {
+    if (resource == "screenContext")
+        return m_integration->screenContext();
+
     return 0;
 }