Fixes #5488 - fixed hook deprecation warning

- code from installer executable was moved to hooks
- services details in post-install message printed out on success only
this is no longer needed, see https://github.com/theforeman/kafo/blob/master/lib/kafo/configuration.rb#L126,  https://github.com/theforeman/kafo/blob/master/lib/kafo/hook_context.rb#L13

you should be able to use `@kafo.config.module_enabled?(name)`