refactor and improve the round trip computation of multiple SCCs

Problem:
- old solution was slow
- depending on the result of TarjanSCC, new distance tables and new phantom node vectors were created to run tsp on it

Solution:
- dont create new distance tables and phantom node vectors
- pass an additional vector with the information which locations are in the same component and ignore all others

fix bug for scc split computation

algorithms/tarjan_scc.hpp

@@ -201,6 +201,11 @@ template <typename GraphT> class TarjanSCC
         return component_size_vector[component_id];
     }
 
+    unsigned get_component_size_by_id(const unsigned component_id) const
+    {
+        return component_size_vector[component_id];
+    }
+
     unsigned get_component_id(const NodeID node) const { return components_index[node]; }
 };