Adding KNNClassificationDecider

[david-z-shi]

Reference issue

Closes #461.

Type of change

Adding KNNClassificationDeciders.

What does this implement/fix?

Adding experiments for KNNClassificationDecider and the associated deciders for these experiments

Additional information

Experiments need more compute and reps.

[david-z-shi]

@jdey4 Let me know if I need to make any other changes.

[david-z-shi]

Yep, everything here and here is new, and there are additional transformers, voters, and deciders in here.