install/58357: The new DVD install images are not documented

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         58357
>Category:       install
>Synopsis:       The new DVD install images are not documented
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jun 21 14:50:00 +0000 2024
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current >= April 2024
>Organization:
  
>Environment:
System: NetBSD
Architecture: sparc64
Machine: sparc64
>Description:

In April, the install ISO images of some NetBSD ports were split into
a DVD and a non-DVD one, but as far as I can tell, the INSTALL
documents for the affected ports do not explain the differences
between the two, or offer guidance as to which one you should use.

In addition to the potential confusion for human users, the TNF
sparc64 testbed is also currently broken because it is trying to
install from an ISO and when it finds two of them, it does not know
which one to use.

I could work around this in the testbed, but I'm trying to abide by
the principle of only working around bugs once they have been
reported, hence this PR.

>How-To-Repeat:

>Fix: