Configurable 40mm fan duct / mount for Wade's extruder

This is a complete redesign of thing #154834 by WeSo (Juan Diego), an adjustable 40mm fan duct / mount for Wade's extruder (but can also be used with any Bowden or direct drive extruder). I kept all the parts compatible/exchangeable with the previous (already good) design. All the parts have been slightly improved (nut traps, reinforcements, better fit and less useless material) and the fan duct itself is a more rounded design with slightly better airflow, but most importantly I wrote from scratch the OpenSCAD source code for all the parts and licensed the code under GPLV3, so it can be edited/modified to taste. The (optional) nice fan guard in the pictures is thing #516392. The eighth picture shows the result of my first ever attempt, without any specific calibration, at printing the infamous bridge torture test (thing #12925) by triffid_hunter. The nineth picture shows the original fan assembly interfering with the X-axis idler, this is solved by adding a pivot joint which als