Add function to translate geometrical identifier hash to positional one for CSCs

Hi,

this MR adds a function to the CscIdHelper to translate geometrical identifier hashes to positional ones. The unit test also tests the conversion for module/detectorElement and channel hashes and shows that the conversion works. Adding @sroe and @jojungge who might want to have a look at the function to tell if one can make the search faster.

Best, Nico