Slightly Beefier E3D-v4.1 30mm Fan Duct

Not much to say other than I wasn't satisfied with the feel and fit of the printed duct that came with my E3D v4.1 hotend.

I re-created the model using FreeCAD to have a bit tighter grip on the cooling fins as well as a bit more material for the fan screws. Overall there is just a bit more material throughout the design.

The holes are intended to be tapped M3, but #6 US should also work.