Add support for split modules in alignment
Following ATLIDTRKCP-519. Add use of (already implemented) addSplitAlignment so that ITk Strip modules which are split into multiple readout elements can have those elements sharing an AlignableTransform (the individual readout elements being part of the same silicon wafer, meaning they are physically bound together and should not be aligned with respect to one another).
This could also be used for any other case where the readout elements are not individually alignable.