this MR is a manual sweep of !27497 (merged) into 21.0. It adds a CscRawDataCnv_p4 converter since we moved from using CSC identifier hashes which reflect the geometrical position of the CSCs to the actual index of the identifier in the vector of identifiers (positional hash) in !24467 (merged) in master.
For 21.0, we want to keep the old geometrical channel identifier hashes as baseline in the transient format. Thus only the _p4 version of the converters translates positional identifier hashes from the persistent p4 files back to geometrical channel identifier hashes needed by the 21.0 transient model. There is also a transToPers() implementation for p4 which however is not the default for 21.0.
The content of the CscRawData still stays as in version p3, just the meaning of m_hashId changes from geometrical to positional hash.
