[6.x] Allow appending of rows to Artisan tables

[adam-prickett]

As a fix to the issue @freekmurze raised (laravel/ideas#2064) on using appendRow() on a Table within Artisan commands, this PR enables that feature by passing a ConsoleSectionOutput to the Table constructor, thus creating a new section.

The Table instance is also now returned following render, which allows appendRow() to be called on the rendered table.

Example:

public function handle()
{
    $table = $this->table(
        ['Column', 'Another column'],
        []
    );

    $table->appendRow(['Value', 'Another Value']);
    $table->appendRow(['Value', 'Another Value']);
}

Output:

+--------+----------------+
| Column | Another column |
+--------+----------------+
| Value  | Another Value  |
| Value  | Another Value  |
+--------+----------------+

[freekmurze]

@adam-prickett Thank you for this 👍

[taylorotwell]

We may have to revert this. It's been a pretty big disaster and headache ever since just to appease this one small use case. Breaking the build on master branch now because of failure to implement some stream methods.