Preparing client platforms

[Lennonka]

https://theforeman-foreman-documentation-preview-pr-3922.surge.sh/nightly/Provisioning_Hosts/index-foreman-el.html#preparing-client-platforms

I don't like that we have many procedures that are essentially all the same. Creating Debian 12 & 11 and Ubuntu 24.04 & 22.04 are effectively all the same, just different on what you need to fill in where.

I know you didn't change this, but could we have a single "Creating operating system" procedure and then an appendix with a table that tells users what they can fill in?

Originally posted by @ekohl in #3922 (review)

[Lennonka]

@maximiliankolb Would you like to work on this one?

[maximiliankolb]

@Lennonka Yes. I worked on this in the past but somehow my PR got nowhere: #3804.

I agree with a single procedure that uses attributes & is very generic; and a table for upstream with the most common default OS repositories.