Listing dataset files and dataset filesize with sda-cli

[aaperis]

As a user
I want to list the datasets that I have access to and the files therein and their sizes using the cli tool
so that I can plan how to proceed with downloading files.

Description:
Extend the list module with a flag list --datasets that returns the relevant info to the user

A/C;

• sda-cli list --config configfile --url <download.se> --datasets gives the datasets the user has access to
• sda-cli list --config configfile --url <download.se> --dataset ABC gives the list of filepaths/fileID, their size and the dataset size