Feature: #102631 - Introduce AsController attribute to autoconfigure backend controllers

See forge#102631

Description

A new custom PHP attribute \TYPO3\CMS\Core\Attribute\AsController has been introduced in order to automatically tag backend controllers, making them available in the service container and enabling dependency injection.

Instead of adding the backend.controller manually, the attribute can be set on the class:

use TYPO3\CMS\Backend\Attribute\AsController;

#[AsController]
class MyBackendController {

}

Note

The attribute is a drop-in replacement for the deprecated \TYPO3\CMS\Core\Attribute\Controller attribute.

Impact

It's now possible to automatically tag a backend controller by adding the new PHP attribute \TYPO3\CMS\Backend\Attribute\AsController.