Implement StableForestRegressor

[rikhuijzer]

Follow-up on #16.

Works towards #13.

Results

13×7 DataFrame
 Row │ Dataset   Model                   Hyperparameters    `nfolds`  AUC     RMS     1.96*SE
     │ String    String                  String             Int64     String  String  String
─────┼────────────────────────────────────────────────────────────────────────────────────────
   1 │ blobs     LGBMClassifier          (;)                      10  0.99            0.01
   2 │ blobs     LGBMClassifier          (max_depth = 2,)         10  0.99            0.01
   3 │ blobs     StableRulesClassifier   (n_trees = 50,)          10  1.00            0.00
   4 │ titanic   LGBMClassifier          (;)                      10  0.87            0.03
   5 │ titanic   LGBMClassifier          (max_depth = 2,)         10  0.85            0.02
   6 │ titanic   StableForestClassifier  (n_trees = 1500,)        10  0.85            0.02
   7 │ titanic   StableRulesClassifier   (n_trees = 1500,)        10  0.83            0.02
   8 │ haberman  LGBMClassifier          (;)                      10  0.71            0.06
   9 │ haberman  LGBMClassifier          (max_depth = 2,)         10  0.67            0.05
  10 │ haberman  StableForestClassifier  (n_trees = 1500,)        10  0.70            0.05
  11 │ haberman  StableRulesClassifier   (n_trees = 1500,)        10  0.67            0.04
  12 │ boston    LinearRegressor         (;)                      10          0.70    0.05
  13 │ boston    StableForestRegressor   (;)                      10          0.66    0.07