Draft: clearly marking IDs and indices in FTChannelID

Making clear in the software when a number is an ID (unique, logical identifier of an element e.g. 1 for station T1), a global index (unique, possibly illogical, starting at 0, sequential, e.g. 0 for station T1, or 13 for second quarter of the 4th layer), or a local index (not unique, but an index, e.g. 1 for the second quarter of the 4th layer).

Goes with LHCb!3566 (closed) and Rec!2889 (closed)

#25 LHCBSCIFI-178 LHCBSCIFI-176

Detector/FT/include/Detector/FT/DeFT.h

@@ -120,8 +120,8 @@ namespace LHCb::Detector {
      *  @return Pointer to the relevant station
      */
     [[nodiscard]] const std::optional<DeFTStation> findStation( const FTChannelID& aChannel ) const {
-      return ( to_unsigned( aChannel.station() ) < this->access()->m_stations.size() )
-                 ? &( this->access()->m_stations[to_unsigned( aChannel.station() )] )
+      return ( to_unsigned( aChannel.stationID() ) < this->access()->m_stations.size() )
+                 ? &( this->access()->m_stations[to_unsigned( aChannel.stationID() )] )
                  : std::optional<DeFTStation>{};
     }