Feature: #69855 - Dispatcher for Backend Routing added

See forge#69855

Description

The previously introduced Backend Routing is updated so that Routes must be defined with a class name and method name, or a Closure / callable. The controller/action or closure is now named as "target".

Example from EXT:backend/Configuration/Backend/Routes.php

// Logout script for the TYPO3 Backend
'logout' => [
	'path' => '/logout',
	'target' => Controller\LogoutController::class . '::logoutAction'
]
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Impact

Each method that is registered will receive both the Request object and the Response object which can be manipulated for output.

The fixed ControllerInterface is not needed anymore and will be removed.