v0.93

This PR contains API changes alongside convenience and performance features:

• BlueCast & BlueCastRegression do not require the target column name during class instantiation anymore.
• t-SNE & PCA plots will scale input data automatically if not disabled by the user
• add eta param in grid search fine tuning
• raise max_depth in Xgboost param default
• add category encoding orchestration: If cardinality of a categorical column is below/equal a certain threshold, onehot encoding will be assigned, otherwise target encoding