Add query logging.

Three new options added
- log_queries, if true log queries, defaults to false
- log_queries_filename, the file where queries are logged, defaults to `queries.log`
- log_queries_threshold, only log queries that run slower than threshold (in milliseconds)
  defaults to 0, i.e. log all queries.
Because we do the same thing in ronjaCompiler, prior to this we added the listener twice (or actually three times because ServerExecutionEngine by extending ExecutionEngine actuall triggers this code twice)