Anet A8 Dual Extruder Lower Fan Duct V1 for Probe

Based on NVBigBlue's Anet A8 Dual Extruder project, this remix allows an Inductive Probe with a 12mm diameter body (LJ12A3-4-Z/BX) to be mounted on the hotend's part cooling fan duct.
I have also included the Upper Fan Duct adaptor to allow a 40mm blower-type fan to be mounted at the side of the pair of E3D V6 hotends. A 2.5mm hole will need to be drilled in the main body of the Hotend framework, and a 3mm screw tapped in to secure the blower fan.