BQ Hephestos Lead screw upgrade

There are a couple lead screw upgrade solutions already for the i3. However the BQ i3 design is slightly different, so all those designs won't work out of the box. Instead of rebuilding the whole printer on an other design I started with the bq design files and modified them in a way so I can use lead screw on Z axis.

Top of the leadscrew should be left to move freely. It won't move, but in case if it does, it's still better to have it move freely. Fixing it would mean the movement have to be