Admidio: IDOR in documents-files.php allows cross-folder file rename and description changes by unauthorized uploaders

Admidio is an open-source user management solution. Prior to version 5.0.10, `modules/documents-files.php` mode `file_rename_save` shares the same root-cause shape as the cross-folder move bug (`05-documents-cross-folder-move-idor.md`): the top-level rights check at lines 79-89 validates `hasUploadRight()` on the URL parameter `folder_uuid`, but the rename operation acts on `file_uuid` — a separate URL parameter — without re-checking the folder that actually contains the file. `DocumentsService::renameFile()` resolves the target file via `getFileForDownload()` (which permits view-readable files) but does not require upload right on the file's source folder. Result: a user with upload right on any folder A can rename a file in folder B as long as they can view it. They can also overwrite the file's description. Version 5.0.10 contains a fix.