Filter for model in 'table join model'

[ea-rus]

Fixes #304.

It is possible to apply filter for model as in example:

SELECT *
FROM example_db.demo_data.home_rentals as t 
JOIN mindsdb.home_rentals_model as m
where m.days_on_market = 13
LIMIT 10;

Here is filter 'm.days_on_market = 13' will be appied on dataframe after joining model with table