Empty state for Packages screen

We could improve the presentation when a user clicks on Packaging but hasn't pushed anything yet.

I think the first iteration of this would be:

1. A friendly empty state image
2. A short description of what this does, and a link to documentation
3. We should also plan to easily support a button to make the required changes for you: https://gitlab.com/gitlab-org/gitlab-ee/issues/5814

Design:

Measure spec previews

SVG