Chooses a default acquisition function optimizer. Defaults to wrapping bbotk::OptimizerBatchRandomSearch allowing 10000 function evaluations (with a batch size of 1000) via a bbotk::TerminatorEvals.
default_acqoptimizer(acq_function)AcqOptimizer
(AcqFunction).
Other mbo_defaults: 
default_acqfunction(),
default_gp(),
default_loop_function(),
default_result_assigner(),
default_rf(),
default_surrogate(),
mbo_defaults