Simplify use_time_management() and allow composing

like other `go` commands wtime/btime can now be composed.

`go depth 10 wtime 100`

will let the engine use standard time management but stop if depth 10 is reached.

fixes https://github.com/official-stockfish/Stockfish/issues/2767

closes https://github.com/official-stockfish/Stockfish/pull/2768

No functional change

src/search.h

@@ -91,7 +91,7 @@ struct LimitsType {
   }
 
   bool use_time_management() const {
-    return !(mate | movetime | depth | nodes | perft | infinite);
+    return time[WHITE] || time[BLACK];
   }
 
   std::vector<Move> searchmoves;