Implement Doctrine DQL converter

[jclaveau]

• implement a trait for repositories (or find a better way to overlaod findBy)
• add support for filters in findBy() methods / make a bridge between Doctrine Criteria class and filters?
• Convert operation fields to doctrine operations

return $this->repository->findBy(
    array('status' => 1, 'flag' =>1, 'contentType' => 'news'),
    array('created' => 'DESC'),
    $limit
);

• Related question concerning Doctrine API: https://stackoverflow.com/questions/30341597/or-operator-in-find-by-doctrine#30349711
• find by implementation: https://github.com/doctrine/orm/blob/master/lib/Doctrine/ORM/EntityRepository.php#L116-L134

TODO

• add doctrine as dev dependency
• implement Converter to create Doctrine Criteria
• Support rules on columns or entity getters
• Overload find
• Integration tests for native dql on columns, sql on entity, dql on entities with relation

[jclaveau]

The toughest point would probably be how to match against column name in DB or doctrine getter.

See https://github.com/jclaveau/php-logical-filter/blob/master/tests/functionnal/LogicalFilterTest.php#L1599-L1600