Improve.source.doctrine.qb

As an idea for simply field aliasing for doctrine query builder:

at configure grid $headers it's not possible to set column names from JOINED tables because this one could have same names as in root table.  

user
   :name

country
   :name

```php

'name' => [
	'tableAlias' => 'c',
    'title' => $translator->translate('Company'),
    'filters' => 'text',
],
'postCode' => [
    'tableAlias' => 'a',
    'title' => $translator->translate('Post code'),
    'filters' => 'text',
    'width' => 100
],
'city' => [
    'tableAlias' => 'a',
    'title' => $translator->translate('City'),
    'filters' => 'text',
],
'country' => [ // here is a problem we need a name of company and can not
    'tableAlias' => 'l.name', // this is new in Doctrine QB at order() used as is no needed concatenate country string from header name
    'title' => $translator->translate('Country'),
    'filters' => 'text',
],

```

specially for ordering, filters used only if any exists in user land code.