Self Hosted - Add SAST for all users projects

How I can add vulnerability scanner for all projects storing on self hosted gitlab.

The best example what I need is analog of github - Dependabot alerts for vulnerable dependencies
No need to check all code just depndencies (composer.json, package.json).
Gitlab version - 13.5.3

Include the SAST template in the each project .gitlab-ci.yml file.
If you are on Premium or higher you can use required-pipeline-configuration