LArCellRec: MIgrate to CaloDetDescManager in CondStore

This is part of the migration of all clients of the CaloDetDescrManager, initiated by @tsulaia.

The LArCellRec package has three usage of the CaloDetDescrManager:

• LArCellMakerFromLArRawChannel: Classical case, migrated to ReadCondHandle(Key)
• LArNonLinearity used the Manager only to get hold of identifier helpers which can be obtained directly
• LArCellEmMiscalib is more tricky. It caches stuff that depends on geometry in initialization. The proper solution would be to put the cache in the CondStore by splitting this tool in a CondAlgo and an AlgTool. That looks like an overkill to me because this tool is not used in any recent production workflow and it's meant only for simulation where the alignment doesn't change. I decided that std::once is a simple solution good enough for this purpose.