chore(SubmodelProxyModel): Marked as deprecated

storybook/pages/SubmodelProxyModelPage.qml

@@ -13,6 +13,7 @@ Item {
     id: root
 
     readonly property string intro:
+        "<b>THIS MODEL IS DEPRECTAED. Use ObjectProxyModel instead</b><br>" +
         "The example uses two source models. The first model contains networks"
         + " (id and metadata such as name and color), visible on the left. The"
         + " second model contains tokens metadata and their balances per"

ui/StatusQ/include/StatusQ/submodelproxymodel.h

@@ -11,7 +11,12 @@
 class QQmlComponent;
 class QQmlEngine;
 
-class SubmodelProxyModel : public QIdentityProxyModel
+/**
+ * NOTE: This proxy model is deprecated and will be removed soon. Use
+ * ObjectProxyModel instead.
+ */
+class QT_DEPRECATED_X("Use ObjectProxyModel instead") SubmodelProxyModel
+    : public QIdentityProxyModel
 {
     Q_OBJECT