Hit transform matrix

This MR introduces transformation matrices that are used to transform charge deposit positions obtained from Geant4 during DepositionGeant4::process_hit.

This transformation accounts for the possible mismatch of sensor coordinate axes in Geant4 and the intended orientation in Allpix (eg. sensor thickness not being the z-dimension, as Allpix expects). A transformation matrix is calculated for every detector model class during the DepositionGeant4Module::construct_sensitive_detectors_and_fields stage.

Currently implemented detector models (Hybrid and Monolithic) are not affected - their transformation matrix is identity. If necessary, newly implemented detector models should add the appropriate transformation matrix in DepositionGeant4Module::calculate_hit_transform(), otherwise the default (identity) matrix is used.

(These changes result from discussion on !528 (closed))