I tried my best to get the right author based on git commit history, but
in the case of code being moved from one file to make another I might
have gotten something wrong.
Replace the boolean skip_extra_repos with a new with_extra_repos
argument that can be default, enabled or disabled.
This will be used to explicitly enable extra repos in a package search
even if systemd is currently disabled, so we can display a hint when a
package was not found because systemd is disabled in a follow-up patch.
