Adds a new type of transformer that is able to transform a column in any table. For example you might have this scenario:

scenario: Check user age
  Then the users ages should be:
    | user   |  age  |
    | john   |  21   |
    | peter  |  34   |

And this transformer:

#[Transforrm('column:user')]
public function transformUsernameToUser(string $username): User
{
    return $this->getUserByUsername($username);
}

Then this transformer will be called to transform any data in the column named user

The final result which is passed to the step that uses this transformer is an array of rows where the data for the column user will be the transformed user. So, for example the step could be implemented like this:

#[Then('the users ages should be:')]
public function checkUsersAges(array $table): void
{
    foreach ($table as $row) {
        Assert::assertSame($row['user']->getAge(), $row['age']);
    }
} 

This transformation can be applied to different tables as long as the column name matches.

The transformation can be applied to more than one column if you list more than one column name in the Transform definition, for example:

#[Transforrm('column:user,other user')]

More than one transformation can be applied to different columns of a table, so in the example above if we had another transformation defined for the age column it would also be applied. The end result is again an array where in each row any column that matched any of the transformations has been replaced with its transformed value

Before implementing this new feature I modified the existing tests for the transformations to adopt the new format where the tests are defined using real files in the fixtures folder. This has been done in a separate previous commit to make it easier to review

With this feature we can get the functionality described in #1229

Once this is merged, I will update the documentation for this transformer (and also other transformers like the row transformer which are not documented)