Enable Saving Segment Related Information In Runtime Connections

In particular, create data members for storing the segment number
and the tubing lengths.  It is likely that we'll need to amend this
information as need arises.

Author: bska

opm/simulators/wells/RuntimePerforation.hpp

@@ -35,6 +35,12 @@ struct RuntimePerforation
 
     /// Depth at which the new connection is created.
     double depth{};
+
+    /// Segment number (1-based), if applicable (MS well).
+    int segment{};
+
+    /// MD start/end along branch if applicable (MS well).
+    std::optional<std::pair<double, double>> perf_range{};
 };
 
 } // namespace Opm