[FEATURE] ambient setup for cutout operation

[opensourcecnc]

How many jobs have you run with BlenderCAM?
100+

Is your feature request related to a problem? Please describe.
Sometimes it might be useful to be able to limit the cutout to hold down the piece using clamps. Then change the position of the clamps and do the rest of the cutout, using another operation with a different exclusion area.

Describe the solution you'd like
Being able to setup an ambient curve, just like in the parallel strategy setup.