Improve runner warning
"Is using a shared runner with a private repository a no-go if I want to keep my repo private? All I can find is the cryptic warning "GitLab Runners do not offer secure isolation between projects that they do builds for. You are TRUSTING all GitLab users who can push code to project A, B or C to run shell scripts on the machine hosting runner X.""
Kamil: This was problem in the past. Since we use Docker we have fairly good separation of builds. You are not able to fetch someone others source unless you find or use linux kernel exploit. This will get improved further with upcoming upgrades to shared runners offering: gitlab-com/www-gitlab-com!1722 (merged). Most likely we will run the builds only once on the VM.
We should improve the warning in the interface.