Transform search output to engine callbacks

Part 2 of the Split UCI into UCIEngine and Engine refactor.
This creates function callbacks for search to use when an update should occur.
The benching in uci.cpp for example does this to extract the total nodes
searched.

No functional change

src/main.cpp

@@ -21,9 +21,9 @@
 #include "bitboard.h"
 #include "misc.h"
 #include "position.h"
-#include "tune.h"
 #include "types.h"
 #include "uci.h"
+#include "tune.h"
 
 using namespace Stockfish;
 
@@ -35,6 +35,9 @@ int main(int argc, char* argv[]) {
     Position::init();
 
     UCIEngine uci(argc, argv);
+
+    Tune::init(uci.engine_options());
+
     uci.loop();
 
     return 0;