feature #59377 [Notifier] Add Matrix bridge (chii0815)

This PR was squashed before being merged into the 7.3 branch.

Discussion
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[Notifier] Add Matrix bridge

| Q             | A
| ------------- | ---
| Branch?       | 7.3
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| License       | MIT

Docs PR: symfony/symfony-docs#20548
Recipe PR: symfony/recipes#1374

Added a new notifier bridge for Matrix Synapse.

Whats implemented in this?
- sends message to roomID when roomID or userID or roomAlias (see above) is given as recipient
- fetches roomID of private room when userID is given as recipient, if no room is available it will be created and the recipiant will be invited to join
- fetches roomID when roomAlias is given as recipient

Whats not implemented at the moment?
- end-to-end encryption, all messages will be unencrypted even if E2E enabled in the room.

Commits
-------

af8b15d0d7d [Notifier] Add Matrix bridge

Author: fabpot

DependencyInjection/FrameworkExtension.php

@@ -3005,6 +3005,7 @@ private function registerNotifierConfiguration(array $config, ContainerBuilder $
             NotifierBridge\Lox24\Lox24TransportFactory::class => 'notifier.transport_factory.lox24',
             NotifierBridge\Mailjet\MailjetTransportFactory::class => 'notifier.transport_factory.mailjet',
             NotifierBridge\Mastodon\MastodonTransportFactory::class => 'notifier.transport_factory.mastodon',
+            NotifierBridge\Matrix\MatrixTransportFactory::class => 'notifier.transport_factory.matrix',
             NotifierBridge\Mattermost\MattermostTransportFactory::class => 'notifier.transport_factory.mattermost',
             NotifierBridge\Mercure\MercureTransportFactory::class => 'notifier.transport_factory.mercure',
             NotifierBridge\MessageBird\MessageBirdTransportFactory::class => 'notifier.transport_factory.message-bird',

Resources/config/notifier_transports.php

@@ -36,6 +36,7 @@
         'line-notify' => Bridge\LineNotify\LineNotifyTransportFactory::class,
         'linked-in' => Bridge\LinkedIn\LinkedInTransportFactory::class,
         'mastodon' => Bridge\Mastodon\MastodonTransportFactory::class,
+        'matrix' => Bridge\Matrix\MatrixTransportFactory::class,
         'mattermost' => Bridge\Mattermost\MattermostTransportFactory::class,
         'mercure' => Bridge\Mercure\MercureTransportFactory::class,
         'microsoft-teams' => Bridge\MicrosoftTeams\MicrosoftTeamsTransportFactory::class,