Discovery: Show on dashboard when security tests are not run

Problem

GitLab Auto DevOps runs SAST/DAST/Dependency scanning/Container scanning by default.

We won't force people to run it, but organizations want to ensure that everything they deployed is tested.

The security dashboard should show untested applications.

Current Proposal

i layout	ii aside, general	iii aside, overflow/hover	iv no Results	v visual
"Project scanning" aside in layout - current work on https://gitlab.com/gitlab-org/gitlab-ee/issues/12846 (layout update) and https://gitlab.com/gitlab-org/gitlab-ee/issues/11190 (adding aside)	"Out of date" items are projects that haven't been tested in X days. 5 days could be a starting threshold (X)	Project names link to project landing page. The aside is a fixed height container, with the data in overflow for scroll when needed. ? links to documentation	In the case no results are found that meets the criteria	Visual design, including https://gitlab.com/gitlab-org/gitlab-ee/issues/12846 and https://gitlab.com/gitlab-org/gitlab-ee/issues/11190

Implementation issue: https://gitlab.com/gitlab-org/gitlab-ee/issues/13298