Fix removal of fos_rest.exception.twig_controller when templating/twig is not enabled

[Tobion]

Fixes #1772, #1887, #1945, #2002

With that you can remove

framework:
    templating:
        engines: twig

which fixes the deprecations and it will use \FOS\RestBundle\Controller\ExceptionController instead of \FOS\RestBundle\Controller\TwigExceptionController correctly. This in turn means it does not use the TwigBundle error rendering but the implementation using the Serializer (Symfony or JMS). But the error response stays the same because of \FOS\RestBundle\Serializer\Normalizer\ExceptionHandler::convertToArray (or the equivalent for Symfony serializer).
So people can disable templating and twig and error rendering should still be BC.

The following part is not needed anymore with #2015
If people use TwigBundle but want to disable SF templating part to get rid of deprecations, they need to set

fos_rest:
    exception:
        exception_controller: 'fos_rest.exception.controller::showAction'

because otherwise the unwanted twig controller get's used again:

FOSRestBundle/DependencyInjection/FOSRestExtension.php

Lines 360 to 367 in 6013d51

	if ($config['exception']['exception_controller']) {
	$controller = $config['exception']['exception_controller'];
	} elseif (isset($container->getParameter('kernel.bundles')['TwigBundle'])) {
	if (Kernel::VERSION_ID >= 40100) {
	$controller = 'fos_rest.exception.twig_controller::showAction';
	} else {
	$controller = 'fos_rest.exception.twig_controller:showAction';
	}

[Tobion]

Test failures unrelated and already failed before...

[Tobion]

For Symfony 4.4 compatibility we likely can remove/deprecate parts of the exception controllers and listeners etc as it will be obsolete with the new ErrorRenderer component. But that is a future topic to handle.

[GuilhemN]

Looks good to me as well 👍

[xabbuh]

Thank you @Tobion.