Implement dream complication settings.

This component allows the user to select dream complications to
enable/disable.

Bug: 215703483
Test: locally on device
Change-Id: I03dd9d67b4aeb3f41885b42391d97c18bd7465f6

src/com/android/settings/dream/IDreamItem.java

@@ -25,11 +25,14 @@ interface IDreamItem {
 
     void onItemClicked();
 
-    void onCustomizeClicked();
+    default void onCustomizeClicked() {
+    }
 
     Drawable getPreviewImage();
 
     boolean isActive();
 
-    boolean allowCustomization();
+    default boolean allowCustomization() {
+        return false;
+    }
 }