Parallel downloading for iso`s

[ar005]

Parallel downloading for iso`s.

The current implementation of iso_download(download_file), is slow and it shows no progress as its downloaded.
Not able to know is its being downloaded or not or checking how much is left, is annoying, sure i can estimate it by hopping over to network usage tools.

Proposed solution

Implement a parallel download function or use external tool like axel [https://github.com/axel-download-accelerator/axel] or use threading for parallel downloading using chunks and use tqdm

[LM-CT]

I was thinking of integrating aria2 for this purpose, but don't know if this would add too much overhead in dependencies.

Using aria2p (the Python library for interacting with aria2) we can add more files to a download queue, which would be very nice if/when more ISOs/VMs are added to the supported analysis environments.

[cert-ee-raidar]

@ar005 and @LM-CT
We will consider this feature. Thank You both for the suggesstions.