Merge solver code with static interface

- Breaks backwards compat solver code with last version. Concurrent broke backwards compat because of race conditions with rng, but single is now broken too, despite it being 2x faster (!!!!)
- Literally twice as fast as Rust now in single thread
- Concurrent doesn't work yet, deadlocks somewhere..?

Solver/Crafty/ISolver.cs

@@ -0,0 +1,12 @@
+using Node = Craftimizer.Solver.Crafty.ArenaNode<Craftimizer.Solver.Crafty.SimulationNode>;
+
+namespace Craftimizer.Solver.Crafty;
+
+public interface ISolver
+{
+    abstract static void LoadChildData(Span<float> scoreSums, Span<int> visits, Span<float> maxScores, ref Node[] chunk, int iterCount);
+
+    abstract static bool SearchIter(ref SolverConfig config, Node rootNode, Random random, Simulator simulator);
+
+    abstract static void Search(ref SolverConfig config, Node rootNode, CancellationToken token);
+}