Combine support every n layers (or Automatically combine support)

[beelsebob]

Is your feature request related to a problem? Please describe.
You guys recently added early support for printing infill with a chonky nozzle to speed up prints. It seems like this could equally well be applied to supports, but the support for supports isn't there yet. With infill, along with specifying a different nozzle to print infill with, you need to specify to combine infill every n layers (possibly automatically).

Describe the solution you'd like
A similar, "Combine support every n layers" setting.

Describe how it would work
Scenario:
Extruder 1 is 0.25mm, has PETG loaded.
Extruder 2 is 0.8mm, has PETG loaded.
Extruder 3 is 0.8mm has soluable support material loaded.

Perimeters are set to print with extruder 1.
Infill with extruder 2.
Supports with extruder 3.
Support interfaces with extruder 1.

Layer height is set to 0.12mm.
Infill settings are set to combine infill every 5 layers, resulting in 0.6mm infill layers.
Support settings are set to combine support every 5 layers, resulting in 0.6mm support layers
Support interfaces are set to still use 0.12mm layers to match the perimeters

The idea here being that while this would result in supports that use more plastic, they would print much faster, and be much more sturdy.