Fan Duct Hypercube Prusa i3 MK3 Style

I merged the fan duct of the Prusa i3 MK3 and of the Hypercube. I made some optimizations:
- flow duct at the bottom (see screenshot)
- bottom is only 0.4 mm thick (instead of 1mm), you have to be careful with the first layer
- minor fixes for easier print

It fits with silicone sock and inductive probe.

I tested the flow with water, but i don't know if it is transferable to air. With water it looks good. Printed few things with it, worked very well so far.

Fusion 360 file is attached