Move core apps from OC_Log::write to OCP\Util

apps/files_external/lib/config.php

apps/files_sharing/ajax/list.php

apps/files_sharing/ajax/publicpreview.php

apps/files_sharing/lib/helper.php

apps/files_trashbin/ajax/delete.php

apps/files_trashbin/ajax/preview.php

apps/files_trashbin/ajax/undelete.php

apps/files_trashbin/lib/trashbin.php

apps/files_versions/ajax/preview.php

apps/provisioning_api/lib/groups.php

apps/provisioning_api/lib/users.php

apps/user_webdavauth/user_webdavauth.php