title	issue
Add system config webhook	NEXT-26080

Core

Added new webhook app.config.changed to react as app for system config changes.

Next Major Version Changes

Changed the following classes to be internal:
- \Shopware\Core\Framework\Webhook\Hookable\HookableBusinessEvent
- \Shopware\Core\Framework\Webhook\Hookable\HookableEntityWrittenEvent
- \Shopware\Core\Framework\Webhook\Hookable\HookableEventFactory
- \Shopware\Core\Framework\Webhook\Hookable\WriteResultMerger
- \Shopware\Core\Framework\Webhook\Message\WebhookEventMessage
- \Shopware\Core\Framework\Webhook\ScheduledTask\CleanupWebhookEventLogTask
- \Shopware\Core\Framework\Webhook\BusinessEventEncoder
- \Shopware\Core\Framework\Webhook\WebhookDispatcher