Bug#902668: Draft for rewrite of https://www.debian.org/CD/verify

Hi,

I've reviewed the proposed patch, and I think it should be applied as
soon as possible.

It seems Laura was waiting for a final review before applying this patch
(long overdue!), which IMHO would bring much more clarity to the image
verification process (usually, a big struggle to new users).

We should make a decision about the long key IDs request (points 1 and 2
from #851541), and once those changes go online, I think both bugs could
be closed (#902668 and #851541).

Thanks for all who have invested energy to clarify this process, and I
hope we can benefit from your work very soon!

Cheers,

Tassia.