the training_kwargs in VariationalStates are unused

Created by: vigsterkr

There's a dictionary parameter for MCState called training_kwargs that based on my understanding is for setting the variables that are going to be passed when training a model. this parameter is being saved as a frozen dictionary in MCState but i don't see it being used anywhere in the code-base.

this parameter is to be deprecated or just the feature was never finished? as i'd like to use a dropout layer in my model and would like to be able to pass an is_training boolean parameter when the model is being trained.