Add adaptions for 3gap RPC chambers
this MR adds adaptions to MuonReadoutGeometry
and MuonGeoModel
in master to allow to simulate BIS78 (i.e. 3-gap RPC chambers). It is basically a manual sweep of the changes proposed by @mnegrini in his MR !29717 (closed) into 21.3 (by doing some cleanup and fixing backwards compatibility). So, I prefer to start with this MR into master and then propagate it into 21.3 and 21.9.
Best, Nico
Edited by Nicolas Koehler