Add typed events for the filesystem/scanner

apps/files/lib/BackgroundJob/ScanFiles.php

apps/files/lib/Command/Scan.php

apps/files/lib/Command/ScanAppData.php

lib/composer/composer/autoload_classmap.php

lib/composer/composer/autoload_static.php

lib/private/Files/Utils/Scanner.php

lib/public/Files/Events/BeforeFileScannedEvent.php

lib/public/Files/Events/BeforeFolderScannedEvent.php

lib/public/Files/Events/FileCacheUpdated.php

lib/public/Files/Events/FileScannedEvent.php

lib/public/Files/Events/FolderScannedEvent.php

lib/public/Files/Events/NodeAddedToCache.php

lib/public/Files/Events/NodeRemovedFromCache.php

tests/lib/Files/EtagTest.php

tests/lib/Files/Utils/ScannerTest.php