fysetc ext mos module (mosfet) bottom cover

Simple bottom cover for fysetc mosfet board module.
You'll need 4pcs M3x8 screws and 4 nuts to secure board on it.

UPDATE: Added new version (v2)
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Differencies from v1:
* The whole design now is much more smooth
* No more thin sidewalls
* 2040-extrusion friendly

You'll still need 4\*M3x8 screws and 4\*M3 Nuts.
2040 profile mount will also require 4\*M4x10 Hex screws + 4\*M4 T-Nuts