Eva Hotend (Remix)

This is a remix of https://2.eva-3d.page/drives/bmg/.
The reason for that:
In my case, I found in practice that the solution was very complicated to assemble and disassemble, as well as the whole assembly was very weak.
This is working on my printer without the problems the original parts had, meaning everything is more robust and doesn't wobble.
For example, the part top_mgn12_v3.stl is more robust and should be printed right or left side down, with at least 3 walls and infill of 50% or more. If it is printed in the natural position, it loses all robustness.
In terms of maintenance, the part that covers the fan does not have screws, but is mounted using a click-type system. This simplifies maintenance of the fan, etc.
In this solution, dismantling the fan with 4 screws no longer means the hotend is loose.
Also, less screws are needed.