Draft: "Smooth" outer perimeters

[philyeahz]

Description

Adds a new parameter called "Outer perimeter layer divider".
This division factor is used to generate sub slices for each layer, which will be used to generate the outer perimeters.

While trying some stuff on the brick layers, I found the need for generating sub slices for slanted walls. Incidentally the outer perimeter "smoothing" could be implemented with this as well.

Not happy with the current state, but it's a start, so someone else could build on it and make it better.
Also tried implementing it the other way around, merging internal layers together,
but adding sub slices to the outer perimeters resulted in less resistance inside the code base.

Screenshots/Recordings/Graphs

Tests

Nozzle: 0.4mm
Layer height: 0.2mm
Outer perimeter layer divider: 2 (Outer perimeter layer height: 0.1mm)

Outer perimeter artifacts are mainly due to inconsistent extrusion speed.

Known Issues

• Only works for classic wall generator (for now)
• No check for minimal nozzle layer height
• Thin wall and small wall detection not implemented for sub slices
• Sub slice height infill will be needed for most accurate results
  • Outer perimeters might float and/or intersect on top infill
  • Top infill can peak out of outer perimeter
• Inconsistent speed on outer perimeters
• Probably many more...