Review, improve usability of our KB on accessing Cloudsmith repo

I am not confident that our kb on using Cloudsmith (https://kb.isc.org/docs/en/isc-kea-packages) is fully adequate.

I think it would hep to add a few cli commands that show how to list what is in the repo, and perhaps some explanation of how to find the correct repo in Cloudsmith.

I have only seen Cloudsmith via the web GUI, and that is not how our users are accessing it. It would help if someone would try to find the appropriate package and version and install from it and see what we can add in terms of instructions about navigation to the KB.

I am not concerned that Cloudsmith is not working - this is just a ticket about the usability, particularly of navigation.