Replace SAST job definition with a vendored template
Problem to solve
Job definition for sast is frozen, and can't be easily updated without creating breaking changes.
With gitlab-ce#53445 (closed), we'll be able to ship a template embedded with each version of GitLab. The template can be updated from one version to another, without impacting our users.
What does success look like, and how can we measure that?
The new official job definition is a one-liner, like:
(syntax will depend on gitlab-ce#53445 (closed))