Task #38086: Enhance TYPO3 bootstrap mechanism
Add module menu object to the TYPO3 backend
The backend at the moment uses a combination of the GLOBAL variables TBE_MODULES and TBE_MODULES_EXT to build the main menus of the backend (the module menu on the left and the submodule menus of the backend modules - look at info for an example).
To be able to easily change the representation of these menus and to offer a clean API for rendering menus the menu is refactored into an object structure with n levels. At the moment the old GLOBALS are migrated to a 3 level menu object. This means that you can use the module menu object in your backend modules to render your submenu.
This patch just adds the object structure and transformation. It does not change any handling of menus in the core itself. These changes can be done piece by piece after this patch.