support ML function

[lizhou1111]

support ML function: stochastic_linear_regression_state and stochastic_logistic_regression_state
For example:

drop stream if exists train_data;
CREATE STREAM IF NOT EXISTS train_data
(
    param1 int,
    param2 int,
    target int
) engine=Memory;
insert into train_data(param1, param2, target) values (1, 1, 1);
insert into train_data(param1, param2, target) values (2, 2, 2);

-- train model
drop stream if exists your_model;
CREATE stream if not exists your_model ENGINE = Memory AS SELECT
stochastic_linear_regression_state(0.01, 0.0, 10, 'Adam', target, param1, param2) AS state FROM train_data;

drop stream if exists test_data;
CREATE stream IF NOT EXISTS test_data
(
    param1 int,
    param2 int
);

-- streaming inference 
WITH (SELECT state FROM your_model) AS model SELECT  
eval_ml_method(model, param1, param2) FROM test_data;

-- insert data into test_data, and it will output the predict value.
insert into test_data(param1, param2) values (3, 3);
insert into test_data(param1, param2) values (4, 4);

About the ML methed arguments, You can refer to this page.You have to give these 4 parameters

This closes #430