nema17 elevation bracket

Based on https://www.thingiverse.com/thing:4664558 but adding a more robust bracket for the elevation motor.

Thanks to jbyrns for the original design!


Edit 30-July-2023
The original design was made with MatterControl. After a report of a broken STL, I ran it through https://www.formware.co/onlinestlrepair and uploaded the resulting STL "nema17-elevation-bracket_fixed.stl". This stl isn't reported as broken in Cura.