Disable SAST checks in Code Quality

With SAST (https://gitlab.com/gitlab-org/gitlab-ee/issues/3723) we have static security checks done in a dedicated job. Some of them (e.g., brakeman, bundler-audit) are also part of Code Quality because they are automatically enabled with codeclimate init.

We can optimize the process and actively disable SAST checks in codeclimate, so they are not run twice: https://docs.codeclimate.com/v1.0/docs/advanced-configuration#section-removing-plugins-from-your-analysis.