[Feature request] DnD widget items in QListView to re-order ⇒ easier than Up/Down

[isf63]

Is your feature request related to a problem? Please describe.
The Up/Down arrows to reorder widgets can become tedious, a QListView D'n'D to reorder would be much easier. The other way to reorder panel items - "Move" option on the actual panel, is not always viable because the widget may be too small or the menu inaccessible.

Describe the solution you'd like
I tried

+++ b/panel/config/configpluginswidget.cpp
+    ui->listView_plugins->viewport()->setAcceptDrops(true);
+    ui->listView_plugins->setDragEnabled(true);
+    ui->listView_plugins->setDropIndicatorShown(true);
+    ui->listView_plugins->setDragDropMode(QAbstractItemView::InternalMove);

but it didn't work.

Describe eventual alternatives you've considered

Context

Polish

Another facilitating polish would be double-clicking on an item to open its configuration.