Add support for Zorin

[wknapik]

Given that the package is apparently available via default repos (or our repo is already added, didn't check), so we shouldn't configure ours and just install right away.

[wknapik]

We might be able to combine that with #52 and just check if the package is available before adding our repo.

[fmarier]

For extrepo, I don't think we want to use the available config because extrepo still doesn't handle key rotations transparently.

In the case of Zorin though, I agree we should install the OS packages right away.

[Smilley27]

Given that the package is apparently available via default repos (or our repo is already added, didn't check), so we shouldn't configure ours and just install right away.