Fix illustration in start GitLab trial panel when no license exists

Summary

Originally from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/5354#note_69901471

If the user doesn't have a license, we show this panel for certain features:

We have to fix the alignment and also look into the illustration to see if it's the most appropriate. I don't know where this panel is being used, other than the milestone pages for the burndown charts.

What is the current bug behavior?

As seen in the image above, the illustration is not aligned and looks odd to its size relative to the white space available.

What is the expected correct behavior?

The illustration should be center aligned. Also, the illustration might not be the most appropriate.