Replace server-pkg-install with pkg-install

[aneta-petrova]

What changes are you introducing?

Simplifying server-package-install to package-install.

Why are you introducing these changes? (Explanation, links to references, issues, etc.)

In #3605, I introduced server-package-install as an attribute for installing packages on the base platform of Foreman server and proxy. When picking, I hit a conflict on 3.8 and noticed that on this branch, a simpler package-install is used for the same purpose.

Anything else to add? (Considerations, potential downsides, alternative solutions you have explored, etc.)

N/A

Checklists

• I am okay with my commits getting squashed when you merge this PR.
• I am familiar with the contributing guidelines.

Please cherry-pick my commits into:

• Foreman 3.13/Katello 4.15 (EL9 only)
• Foreman 3.12/Katello 4.14 (Satellite 6.16)
• Foreman 3.11/Katello 4.13 (orcharhino 6.11 on EL8 only; orcharhino 7.0 on EL8+EL9)
• Foreman 3.10/Katello 4.12
• Foreman 3.9/Katello 4.11 (Satellite 6.15; orcharhino 6.8/6.9/6.10)
• Foreman 3.8/Katello 4.10
• Foreman 3.7/Katello 4.9 (Satellite 6.14)
• We do not accept PRs for Foreman older than 3.7.

[github-actions]

The PR preview for 2ddc56e is available at theforeman-foreman-documentation-preview-pr-3610.surge.sh

The following output files are affected by this PR:

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[maximiliankolb]

Suggested change

	:package-install: {project-package-install}
	:platform-package-install: {project-package-install}

Just a suggestion to align it with the other two options: installing packages on Foreman and installing packages on Clients.

[aneta-petrova]

What I'm trying to do is actually align it with attributes-deb:

foreman-documentation/guides/common/attributes-foreman-deb.adoc

Line 13 in afaf36c

:package-install: apt install

A simple package-install attribute kind of makes sense to me -- as a general install command to be used in any context outside of Foreman? platform-package-install or the current server-package-install are very specific in the sense that they are to be used on the Foreman platform. A more generic package-install would be enough, I think.