Support for additional attack model types in inference attacks

[abigailgold]

Blackbox membership inference attack currently supports 3 model types: nn, rf and gb.
Blackbox attribute inference attack currently supports 2 model types: nn and rf.
Both could benefit from supporting additional attack model types (e.g., KNN, LR, etc.)

[abigailgold]

Also need to replace sklearn MLP implementation in attribute inference blackbox to pytorch (to improve performance).