Breaking: #72405 - Removed traditional BE modules handling 

See forge#72405

Description 

The traditional way of registering backend modules done via custom mod1/index.php and mod1/conf.php has been removed.

Impact 

Calling ExtensionManagementUtility::addModulePath() will result in a fatal error. Additionally, all modules that are registered via ExtensionManagementUtility::addModule() and setting a path will not be registered properly anymore.

$TBE_MODULES['_PATHS'] is always empty now. Additionally, the options script and navFrameScript and navFrameScriptParam will have no effect anymore when registering a module.

Affected Installations 

Any installation using an extension that registers a module via the traditional way using standalone scripts.

Migration 

Use the option routeTarget when registering a module, and PSR-7 equivalent entry-points in module controllers.