* erp5_core: allow to use Base_download from ERP5JS dialog
* erp5_base/dms* move Document_viewDownloadDialog into erp5_base
* erp5_base: add a dialog to download Image.
* erp5_web_renderjs_ui_test: test Dms download actions
* erp5_dms: allow to download original/converted documents from ERP5JS UI