Thin wedge wall for testing Arachne

This is a thin wall wedge for testing the Arachne slicing scheme in PrusaSlicer and Cura.

It has a 100mm long by 2mm high tapering wedge from 2mm to 0mm, and will show:

* The measured length of the printed wedge shows how thin that thin walls can be printed. (PrusaSlicer's min_feature_size)
*the thickness at the thin end shows the minimum perimeter width (PS's min_bead_width)
* The length to the start of the constant thickness section shows the (PS's min_bead_width)
* Discontinuities in the wedge show where Arachne switches to multiple perimeters.

It also works like a toothpick or swizzle-stick.

Also included is wedge_wall_arachne200x2x10.stl -- a 200mmx2mmX10mm wedge wall with a picture showing where my slicer&printer changed perimeter numbers and thicknesses. With the 200mmx2mm wedge, you can measure from the 2mm thick end divide by 100 and subtract from 2.00 to get the designed thickness.

For details on Arachne see https://help.prusa3d.com/article/arachne-p