WIP: Added a preference for displaying devices above places in the sidepane (!447)

Added a preference that after restarting changes the placement of the Places and Devices areas. WIP because it is getting late and I'll go grab something to eat :^). I am not sure if this is the most elegant way to go about this, but it seems decent considering the current handling of the placement of items in the sidepane. This is a very specific fix tailored to just being able to restore the old thunar interface. It could also be extended to incorporate the Network Area.