This PR introduces 3 new features for DND, all configurable via parameter:

• drag_all_nodes: controls whether all nodes are dragged instead of only top level selected nodes (ignoring children of selected nodes)
• preserve_nodes_order: controls whether nodes that are dragged should be kept in the original order from origin tree (when true) or in order of selecting (when false)
• disabled: a boolean indicating if dnd should be enabled or not, useful if you want to dynamically disable/enable editing of the tree

If left not specified, default values are used that do not change anything compared to before commit (non breaking change).