Cleanup and remove systemd use in the setup scripts

[cbosdo]

What does this PR change?

Remove unused code in the setup scripts in order to ease refactoring them. This commit removes the need for systemd running as PID1 to run the setup script.

This also means that mgr-setup has to be called before running the real container and starting everything.

Note that some of the cleanup removing non-SUSE distributions handling, which shouldn't be a problem as Uyuni is now only shipped as a container built on a single openSUSE distro.

GUI diff

No difference.

• DONE

Documentation

• No documentation needed: only internal and user invisible changes

• DONE

Test coverage

• CI needs to be adjusted

• DONE

Links

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Port(s): # add downstream PR(s), if any

• DONE

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[nadvornik]

Maybe whole rhn-config-schema.pl can be dropped. It seems to do nothing in container setup. The output seems to be exactly the same as input.

[cbosdo]

The merge of this PR has to be synchronized with uyuni-project/uyuni-tools#507

[cbosdo]

Maybe whole rhn-config-schema.pl can be dropped. It seems to do nothing in container setup. The output seems to be exactly the same as input.

I have the feeling that the whole schema-override thing is no longer around. @mcalmer can you confirm it?

[mcalmer]

Maybe whole rhn-config-schema.pl can be dropped. It seems to do nothing in container setup. The output seems to be exactly the same as input.

I have the feeling that the whole schema-override thing is no longer around. @mcalmer can you confirm it?

I think so. I never understood how it should work, so we never used it

[cbosdo]

Build tested in OBS and deployment working with the kubernetes operator.