KFilePlacesItem: Add tooltip

Shows the place's path and mountpoint, if applicable, as a tooltip. In case of loop devices, it shows the backing file path (e.g. path to the disk image) rather than /dev/loop123.

Show label in tooltip if it is elided

Show free space info in the tooltip

the same wording as the file properties dialog. This is done in the view as it already has that information available for the capacity bar.

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Exactly how Dolphin does it

However, the tooltips are somewhat annoying imho as they show up when you hover and then remain as you move the mouse about. Dolphin treats each place as an individual item, so the tooltip show timer is reset every time you move between items. Hence RFC as I am not sure we want to have it like this... Fixed with Qt Wayland 6.8