PUBDEV-8179: Added get_best_model to AutoML user guide
PUBDEV-8179: Added get_best_model to AutoML user guide

h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3