feature #35422 [Messenger] Move Transports to separate packages (Nyholm)

This PR was squashed before being merged into the 5.1-dev branch (closes #35422).

Discussion
----------

[Messenger] Move Transports to separate packages

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       |
| License       | MIT
| Doc PR        | coming

I think it is a good idea to have the transports in a separate package. The benefits a many:
- It allows us to have usage statistics
- The core messenger package is smaller
- Transports can have dependencies specified in composer.json instead of just suggests

This PR will not break BC but it requires to configure subtree split.

Commits
-------

2990c8f1e7 [Messenger] Move Transports to separate packages

Author: fabpot

DependencyInjection/FrameworkExtension.php

@@ -81,6 +81,8 @@
 use Symfony\Component\Mailer\Bridge\Postmark\Transport\PostmarkTransportFactory;
 use Symfony\Component\Mailer\Bridge\Sendgrid\Transport\SendgridTransportFactory;
 use Symfony\Component\Mailer\Mailer;
+use Symfony\Component\Messenger\Bridge\Amqp\Transport\AmqpTransportFactory;
+use Symfony\Component\Messenger\Bridge\Redis\Transport\RedisTransportFactory;
 use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
 use Symfony\Component\Messenger\MessageBus;
 use Symfony\Component\Messenger\MessageBusInterface;
@@ -312,6 +314,22 @@ public function load(array $configs, ContainerBuilder $container)
             $container->removeDefinition('console.command.messenger_failed_messages_show');
             $container->removeDefinition('console.command.messenger_failed_messages_remove');
             $container->removeDefinition('cache.messenger.restart_workers_signal');
+
+            if ($container->hasDefinition('messenger.transport.amqp.factory') && !class_exists(AmqpTransportFactory::class)) {
+                if (class_exists(\Symfony\Component\Messenger\Transport\AmqpExt\AmqpTransportFactory::class)) {
+                    $container->getDefinition('messenger.transport.amqp.factory')->setClass(\Symfony\Component\Messenger\Transport\AmqpExt\AmqpTransportFactory::class);
+                } else {
+                    $container->removeDefinition('messenger.transport.amqp.factory');
+                }
+            }
+
+            if ($container->hasDefinition('messenger.transport.redis.factory') && !class_exists(RedisTransportFactory::class)) {
+                if (class_exists(\Symfony\Component\Messenger\Transport\RedisExt\RedisTransportFactory::class)) {
+                    $container->getDefinition('messenger.transport.redis.factory')->setClass(\Symfony\Component\Messenger\Transport\RedisExt\RedisTransportFactory::class);
+                } else {
+                    $container->removeDefinition('messenger.transport.redis.factory');
+                }
+            }
         }
 
         if ($this->httpClientConfigEnabled = $this->isConfigEnabled($container, $config['http_client'])) {

Resources/config/messenger.xml

@@ -67,11 +67,11 @@
             <argument type="tagged_iterator" tag="messenger.transport_factory" />
         </service>
 
-        <service id="messenger.transport.amqp.factory" class="Symfony\Component\Messenger\Transport\AmqpExt\AmqpTransportFactory">
+        <service id="messenger.transport.amqp.factory" class="Symfony\Component\Messenger\Bridge\Amqp\Transport\AmqpTransportFactory">
             <tag name="messenger.transport_factory" />
         </service>
 
-        <service id="messenger.transport.redis.factory" class="Symfony\Component\Messenger\Transport\RedisExt\RedisTransportFactory">
+        <service id="messenger.transport.redis.factory" class="Symfony\Component\Messenger\Bridge\Redis\Transport\RedisTransportFactory">
             <tag name="messenger.transport_factory" />
         </service>