Introduce Groove Factor

[ChRen95]

So the groove factor always is used to calculate the working radius / diameter of a roll pass.
The problem with this groove factor, is that there are models that calculate this factor based on solely the groove.
Like already implemented in pyroll via: self.contour_line.centroid.y (it that case the roll is used but could also be transferred to the groove).
Further models like the simple model from Wusatowksi uses the equivalent area of the outgoing profile as well as the roll gap

$$ \left( \frac{A_{eq, 1}}{w_1} - s \right) $$

So first of all I would implement this model for more clarity. Second my question would be were to put it so on roll_pass or somewhere else and how to name it.