Show secure results on environments page, backend

What does this MR do?

This MR adds links to the secure products reports presents for an environment, so that the frontend can show the user whether the environment is secure or not.

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/issues/4299

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [ ] Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• EE specific content should be in the top level /ee folder
• [ ] For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?