PC per point from geometrical relations as per Singh et al. (2017)

[hakonanes]

We should add a projection/pattern center (PC) calculation method to kikuchipy.detectors.EBSDDetector which populates a map of navigation shape with PCs from the geometrical relations in Eqs. (8) and (9) in Appendix A in Singh et al. (2017).

This could then be used as a first approximation of PCs per point, instead of a constant PC, in orientation and/or PC refinement following dictionary indexing, given that the detector pixel size and navigation step size in both directons are known.