move all the files stuff into a files class

apps/files/ajax/upload.php

apps/files_archive/lib/storage.php

apps/files_archive/lib/tar.php

apps/files_archive/lib/zip.php

apps/files_archive/tests/archive.php

apps/files_archive/tests/storage.php

apps/files_archive/tests/tar.php

apps/files_archive/tests/zip.php

apps/files_encryption/lib/proxy.php

apps/files_encryption/tests/encryption.php

apps/files_encryption/tests/stream.php

apps/files_external/lib/ftp.php

apps/files_external/lib/google.php

apps/files_external/lib/swift.php

apps/files_external/lib/webdav.php

apps/files_external/tests/ftp.php

lib/public/files.php

lib/public/util.php