jp (file): new `get` command + encryption with upload: - new file/get command let download a file from URL. It handles `aesgcm:` scheme by thanks to backend decryption on the fly. - new `--encrypt` option for upload. When used, the file will be encrypted using AES-GCM algorithm, and the `aesgcm:` URL will be returned - for both commands, the XMLUI note is displayed in case of error