Name KiCad zones after selected sketch

[clayton13]

Adds a minor feature that when Fills and KeepOuts are exported from FreeCad they are named after the selected sketch when using KiCadStepUp WB -> Push Sketch to PCB.

It's written using python that I believe would be compatible back to 3.6, if python >3.9 is enforced removing the prefix would be a simpler skn.removeprefix() call.

FreeCad 0.20.2	KiCad 8.0.3-rc3