Adds turn instructions to the turns layer in debug tiles. (#4460)

Add turn types and modifiers to turn points in debug tiles.  Also refactor some of the tile code to reduce some repetition.

include/engine/routing_algorithms/tile_turns.hpp

@@ -24,6 +24,7 @@ struct TurnData final
     const int turn_angle;
     const EdgeWeight weight;
     const EdgeWeight duration;
+    const extractor::guidance::TurnInstruction turn_instruction;
 };
 
 using RTreeLeaf = datafacade::BaseDataFacade::RTreeLeaf;