P3Steel Y belt holder

Belt holder for the Y axis.
To prusa I3 steel, Y axis clamping between the bed and the belt. Designed in two heights and maximizing the useful travel of the bed.
Includes a pretensioner for easy positioning of the belt.
Timing Belt model G2.5

## UPDATED ##
- Corrected the rotation of the parts for printing.
- Added detail to the instructions.