Remove PixelModule and HCRawBankDecoder
In LHCb there was a PixelModule.h, that is also duplicated in Rec as PrPixelModule.h. This class seems to be a relic from a previous iteration of the velo tracking and is no longer actually used.
In addition, there was a DAQ thing around from Herschel, a detector that is no longer there in Run 3.
This MR removes the references to this file, in addition to the HCRawBankDecoder.
Tagging @ahennequ for possible review concerning the PixelModule part.
Goes with Rec!3681 (merged)