Use sda-download's api to get files

[aaperis]

As an sda-admin
I want to have a tool that allows users to download files that they have access to
so that I don't have to manually publicize them.

Description:
sda-cli needs to know which download service api to talk to. The service api URI can be passed as an argument for this issue.

A/C:

• Given a token with the correct visa for a dataset, download a file from /files endpoint (or the relevant file serving endpoint for each specific case) of sda-download.
• The downloaded file is encrypted with the user's key.

Demo;

• download file