[Bookmarks] Add new bookmarks at the end of the folder

Creating new bookmarks in Bookmarks Organizer are still prepended
(inserted at the begin)

src/lib/bookmarks/bookmarks.cpp

@@ -122,7 +122,7 @@ void Bookmarks::addBookmark(BookmarkItem* parent, BookmarkItem* item)
     Q_ASSERT(parent->isFolder());
     Q_ASSERT(item);
 
-    insertBookmark(parent, 0, item);
+    insertBookmark(parent, parent->children().count(), item);
 
     m_autoSaver->changeOcurred();
 }

src/lib/bookmarks/bookmarksmanager.cpp

@@ -293,7 +293,7 @@ void BookmarksManager::addBookmark(BookmarkItem* item)
     BookmarkItem* parent = parentForNewBookmark();
     Q_ASSERT(parent);
 
-    m_bookmarks->addBookmark(parent, item);
+    m_bookmarks->insertBookmark(parent, 0, item);
 
     // Select newly added bookmark
     ui->tree->selectBookmark(item);