Bondtech BMG part1 modified for easier e3d v6 installation

This is an edit of part 1 in https://www.thingiverse.com/thing:3182969

I found the install of the E3D v6 absurdly hard, and did some modifications.
The collet can stay on the v6 in this design.

Also added a slot for a square m3 nut for the tension screw.

Can be printed without supports, the lip for the tensioner will sag a bit, and requires some small amount of cleanup, but no more than if you use supports, i reckon.

If you want to use supports put 8 degrees in Overhang Threshold in