[Feat] Data catalog: distinguish label and name of nodes

[petrasovaa]

Currently, node label is used for most management tasks, e.g. when switching mapset it takes the mapset name from the label (node.label). Instead it should take the name from the data attribute of node (node.data['name']) when appropriate. This way we can use the label to show additional information about the node in the GUI, e.g. number of maps in the mapset, if mapset is locked etc. So the task here is just to review all usages of label and replace it with data['name] if it needs the name of the map/mapset/location/db.