Add options for mixing hotends

[CroaksfromtheMire]

Is there an existing issue for this feature request?

• I have searched the existing issues

Is your feature request related to a problem?

I haven't been able to find a slicer that supports mixing hotends, and I don't know how to write complex Gcode for it.

Which printers will be beneficial to this feature?

All

Describe the solution you'd like

Please add options to create and configure mixing hotends, including the number of inputs, mixing ratios, and gradients. My interest for this for this feature arose from this video:
https://www.youtube.com/watch?v=MY4uHML5pEg

Describe alternatives you've considered

No response

Additional context

No response