move payment factory and redsys.xml from bundle to bridge.

There is no need in the whole bundle, the factory and services xml could be stored in the lib itself. Same approach we did here https://github.com/locastic/TcomPayWayPayum/tree/master/src/Locastic/TcomPayWayPayum/Bridge

And in your app you can add it:

```php
<?php

namespace Acme\RedsysBundle;

use Crevillo\Payum\Redsys\Bridge\Symfony\RedsysPaymentFactory;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\HttpKernel\Bundle\Bundle;

class AcmeRedsysBundle extends Bundle
{
    /**
     * {@inheritDoc}
     */
    public function build(ContainerBuilder $container)
    {
        parent::build($container);

        /** @var $extension \Payum\Bundle\PayumBundle\DependencyInjection\PayumExtension */
        $extension = $container->getExtension('payum');

        $extension->addPaymentFactory(new RedsysPaymentFactory);
    }
}

```