Provide permanent URLs for latest stable ISO

[Jeremy Bícha <jbicha@debian.org>]

Control: clone -1 -2
Control: reassign -2 debian-cd
Control: retitle -2 Provide permanent URLs for latest stable ISO

I am splitting this bug because there is both a task that can be done
in the osinfo-db packaging and a task for the Debian "CD" release
publishing.

I learned this weekend of the existence of
https://cdimage.debian.org/mirror/cdimage/archive/

That provides permanent URLs for the second to newest stable ISO (i.e.
Debian 13.0 instead of 13.1) and for all oldstable (etc) ISOs
(including Debian 12.12 released a few days ago). Therefore, we will
update osinfo-db to use those URLs for now.

Is it possible to also publish the latest stable ISOs there (i.e.
13.1) as is already done with oldstable?

There's also my earlier suggestion about something like a symlink or
redirect like
https://releases.ubuntu.com/noble/ubuntu-24.04-latest-desktop-amd64.iso

Specifically, osinfo-db currently includes Debian URLs for the netinst
and DVD1 ISOs for basically all supported architectures. Also, the
live GNOME amd64 ISO.

Thank you,
Jeremy Bícha