Move more classes to more specific locations.

Moved .model classes to .base.
Deleted some unused classes.
Moved functional tests into a new .funcitonal package.
Followup to 1450250.

Change-Id: Ic087fe4a014d9179fab3dc6f833aaf73373f9452
diff --git a/src/com/android/documentsui/NavigationViewManager.java b/src/com/android/documentsui/NavigationViewManager.java
index 1479ed4..43da967 100644
--- a/src/com/android/documentsui/NavigationViewManager.java
+++ b/src/com/android/documentsui/NavigationViewManager.java
@@ -23,8 +23,8 @@
 import android.util.Log;
 import android.view.View;
 
+import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.dirlist.AnimationView;
-import com.android.documentsui.model.RootInfo;
 
 import java.util.function.Consumer;