Moving all-apps predictions to Launcher model

Predictions are loaded and managed by Launcher model and follow
the model lifecycle. They are then bound to the callback which
handles the UI

Bug: 160748731
Change-Id: I4a3ea0698d80fafe94afb4ce66ffa7f4a6a91c68
diff --git a/res/values/config.xml b/res/values/config.xml
index 75fcc90..dc8bdff 100644
--- a/res/values/config.xml
+++ b/res/values/config.xml
@@ -70,6 +70,7 @@
     <string name="test_information_handler_class" translatable="false"></string>
     <string name="launcher_activity_logic_class" translatable="false"></string>
     <string name="prediction_model_class" translatable="false"></string>
+    <string name="model_delegate_class" translatable="false"></string>
 
     <!-- View ID to use for QSB widget -->
     <item type="id" name="qsb_widget" />